The presidency of the United States is the most extraordinary job ever devised, and it has become an object of the hopes and dreams -- and, at times, the fears, frustration, and anger -- of people around the world. Expectations that the president can solve every problem are obviously unrealistic -- and yet such expectations are a reality that he will have to confront. A successful president must identify meaningful yet achievable goals, lay them out clearly before the nation and the world, and then achieve them through leadership skills that will be tested by pressures unimaginable to anyone who has not held the job. A reactive and passive presidency will not succeed, nor will one in which a president promises solutions but does not deliver -- or acts with consistent disregard for what the Declaration of Independence called "a decent respect to the opinions of mankind."

Although not every issue the new president inherits requires change, every major one requires careful reexamination. In many cases, new policies and new people -- loyal to the president and capable of mobilizing the support of the permanent bureaucracy -- will be necessary. But a comprehensive national security policy is more than a collection of individual positions. A coherent vision for the United States' role in the world must be based on its enduring national interests, its values, and a realistic assessment of its capabilities and priorities; not even the most powerful nation can shape every event and issue according to its own preferences. The days when a single word, such as "containment," could define U.S. foreign policy will not return in this world of many players and many, many issues. Still, there is a need to define a broad overarching concept of the United States' national interests. (The Bush era's focus on the "global war on terror" was simultaneously too limited and too broad.)

To restore the United States to its proper world leadership role, two areas of weakness must be repaired: the domestic economy and the United States' reputation in the world. Although the economy is usually treated as a domestic issue, reviving it is as important to the nation's long-term security as is keeping U.S. military strength unchallengeable. This will require more than a cyclical upturn; to repair the economy in the long term, a new national policy on energy and climate change will be essential. And restoring respect for American values and leadership is essential -- not because it is nice to be popular but because respect is a precondition for legitimate leadership and enduring influence.

The president should address both issues as early as possible in order to strengthen his hand as he tackles pressing strategic issues, including the five neighboring countries at the center of the arc of crisis that directly threatens the United States' national security -- Turkey, Iraq, Iran, Afghanistan, and Pakistan. A few early actions that lie wholly within his authority can make an immediate impact. The most compelling such actions would be issuing a clear official ban on torture and closing the detention facility at Guantánamo Bay, Cuba, which now holds only 260 prisoners. Because the Bush administration limited itself to punishing only those at the very bottom of the chain of command at Abu Ghraib, the damage to the United States' image has been immense and continuing -- the gift that keeps on giving to the United States' enemies. Presidential directives making clear that the U.S. government does not tolerate or condone torture are necessary in order to separate the new administration from that costly legacy. As for Guantánamo, closing it is complicated, as Bush administration apologists (and many lawyers) say. Well, a lot of things in life are complicated. Guantánamo must not become the next president's albatross, too; closing it, no matter how difficult, is not just desirable but imperative.

A NEW FACTOR

History is not immutable. But there is one pattern that comes very close to being a law of history: in the long run, the rise and fall of great nations is driven primarily by their economic strength. Rome, imperial China, Venice, France, the Netherlands, Portugal, the United Kingdom -- all had their day, and their international decline followed inexorably from their economic decline.

Starting in the late nineteenth century, nothing was as important to the emergence of the United States as its spectacular economic growth. That growth was fueled, literally, by cheap domestic oil. The United States always overcame its periodic economic downturns, even the Great Depression. It is therefore reasonable for Americans, who are optimistic by nature, to assume that the nation's current economic difficulties are just another temporary cyclical setback. But a new factor has emerged, unlike any the United States has previously faced. With the price of oil quadruple what it was four years ago, Americans are witnessing -- or, more to the point, contributing to -- the greatest transfer of wealth from one set of nations to another in history. Politicians and the press understandably focus attention on the domestic pressures caused by the high price of oil -- the "pain at the pump." But the huge long-term geostrategic implications of this wealth transfer, so far virtually neglected, also require the next president's attention.

Consider the following, from the noted oil expert Daniel Yergin: the United States consumes more than 20 million barrels of oil a day, about 12 million of which are imported. Based on prices from the first half of 2008, that means the United States is transferring about $1.3 billion to the oil-producing countries every day -- $475 billion a year. (At the more recent price, $140 for a barrel of crude, the amount is far greater.) The other major consumers, including China, the European Union, India, and Japan, are sending even greater portions of their wealth to the producing countries, for a total annual transfer of well over $2.2 trillion. These figures are climbing.

Suppose high oil prices continue for, say, another decade -- a gloomy but not unreasonable scenario given the long lead-time required to wean the consuming nations off their expensive habit. The wealth now accumulating in the producing nations will lead over time not only to even greater economic muscle but also to greater political power. Some of these producing nations have very different political agendas from those of the United States, Europe, and Japan. Groupings of oil-rich nations with goals opposed to those of the United States and its European allies will become more common and act more boldly. More money will be available to fund dangerous nonstate actors who seek to destroy Israel or destabilize parts of Africa or Latin America -- or attack the United States. There is a well-known example of this, although the West seems not to have learned any lessons from it: Saudi Arabia, which, although it has long worked with Washington to bolster world oil output and keep prices within an acceptable range, has simultaneously allowed billions of (ostensibly nongovernmental) dollars to go toward building extremist madrasahs and funding terrorist organizations, including al Qaeda. There will be more such complicated double-dealing in the future: Does anyone doubt that the current assertiveness on the international stage of, for example, Iran, Russia, and Venezuela comes from the economic muscle that accompanies their growing petrodollar reserves? (Venezuela now spends five times as much as the United States on foreign aid to the rest of Latin America.)

At the same time, the problem of climate change has reached a level that, in the view of many scientists, threatens the planet; many believe that there is only a decade to act to avoid a catastrophic tipping point, which would otherwise come somewhere around the middle of the century. Even as former Vice President Al Gore crossed the globe raising the alarm, the Bush administration wasted seven and a half irreplaceable years, refusing to address the issue. There was little sense of urgency in this administration or among its congressional allies; they opposed almost anything other than voluntary conservation measures -- until the prices at the pump hit $4 a gallon. It was only at the end of 2007, under immense political pressure, that the Bush administration finally agreed to the first increase in fuel-efficiency standards in 32 years. (By that time, fittingly, Gore had won the Nobel Prize.) Then, at the 2008 G-8 summit in Japan, George W. Bush agreed to a vaguely worded and essentially meaningless "aspirational" goal on the reduction of carbon emissions.

Over time, stronger conservation measures, together with investments in new technologies, will undoubtedly be put into effect. But if oil and gas prices fall from their current bubble-like levels, consumption will rise again. On the other hand, if prices stay high, consumption may fall, but the United States and its closest allies will continue to hemorrhage petrodollars. Either way, absent an effective energy and climate-change policy, the planet will suffer from continued warming. Drought and famine will increase in some of the poorest places on earth, food prices will continue to rise, and people will abandon areas that are no longer arable. Glaciers and icecaps will melt faster, ocean levels will rise, and more species of plants and animals will become extinct. The Bush administration's neglect of these issues is beyond astonishing -- it is as shocking, in its own way, as the administration's performance in Afghanistan and Iraq.

The two major presidential candidates, Senator Barack Obama (D-Ill.) and Senator John McCain (R-Ariz.), both say that they take climate change seriously. But an examination of their positions on the issue shows important differences. Obama has a far more comprehensive plan, with an ambitious goal for emissions reduction, a market-based mechanism that has broad support among economists on the left and the right, and substantially greater investments than McCain's plan in technologies that will help achieve these goals. McCain stresses removing environmental restraints on domestic and offshore drilling. This is hardly a serious long-term solution to anything; even if major new fields were found, they would have no effect on supply for at least a decade, and they would do nothing for climate change or conservation.

The search for effective energy and climate-change policies will require a national consensus on the seriousness of the situation and an action plan entailing compromises and sacrifices on everyone's part, sacrifices normally associated with war -- all without undermining economic growth. As a cautionary tale, it is worth recalling President Jimmy Carter's fervent but unsuccessful attempt to rally the nation in a prime-time televised speech in April 1977. Wearing a much-mocked cardigan sweater, he said that his energy-independence project would be the "moral equivalent of war." When someone pointed out that the initials of that phrase spelled "meow," the press had a field day, ignoring the substance of Carter's proposals. A true national debate was deferred for 30 years. One of Ronald Reagan's first acts as president was to remove from the White House roof the solar panels Carter had had installed.

The twin challenges of energy dependence and climate change offer an opportunity for a breakthrough between the two most important nations in the world today, which also happen to be the world's top two polluters. Together, China and the United States produce almost 50 percent of the world's carbon emissions. In the last year, China has passed the United States as the world's largest polluter. In 2007, two-thirds of the worldwide growth in global greenhouse gas emissions came from China, according to the Netherlands Environmental Association, which estimates that China now emits 14 percent more climate-warming gases than the United States does. On a per capita basis, however, it is still not even close -- as every Chinese points out. The United States produces 19.4 tons of carbon dioxide per person per year; China (5.1 tons) trails not only the United States but also Russia (11.8 tons) and the countries of western Europe (8.6 tons). India checks in at only 1.8 tons per capita.

The effort to produce a new international climate-change treaty to supplant the Kyoto Protocol, which expires in 2012, is getting nowhere fast. A new agreement is supposed to be finished and ready to be signed in Copenhagen at the end of 2009. Do not count on it. With neither China nor the United States playing a leading role in the negotiations, many members of Congress are warning that there is no greater possibility of Senate ratification for the Copenhagen agreement next year than there was for the Kyoto Protocol in the 1990s (in other words, none) -- unless at least Brazil, China, India, and Indonesia agree to limits on their carbon emissions. And without China and the United States, the value of the treaty, although still real, would be limited.

Here is a seemingly insoluble Catch-22: the major emerging economies will not agree to any treaty containing meaningful limits on their emissions, and the U.S. Senate will not ratify an agreement that does not include them. There is, however, another approach that should be considered, without abandoning the Copenhagen process: multiple agreements in which various combinations of nations address specific parts of the larger problem. In such a collection of agreements, there would be a greater opportunity for genuine U.S.-Chinese cooperation. In particular, the two nations could reach bilateral agreements for joint projects on energy-saving, climate-change-friendly technology. The mutually beneficial goal would be an increase in energy efficiency and a reduction in carbon emissions in both countries. (Japan, the world's most efficient energy consumer -- and an indispensable ally of the United States -- could participate in such arrangements; it has much to teach both nations, and it already has bilateral technology-exchange agreements with China.) From carbon capture to clean coal to solar and wind energy, there is vast untapped potential in joint projects and technology sharing -- but no institutionalized U.S.-Chinese framework to encourage them.

On a recent trip to China, I raised the possibility of such bilateral agreements with senior Chinese officials, who showed interest and a willingness to explore the idea unofficially through nongovernmental channels. Their concern, freely expressed, was that any energy plan the West proposed would be just another device to slow down China's economic growth. Whether true or not, this deeply felt view, shared by India and other major emerging markets in regard to their economic growth, must be understood and taken into account in order to make progress. Perhaps the window is already opening slightly: Wang Qishan, the powerful vice premier in charge of trade and finance, recently called publicly for joint research laboratories for renewable energy and pollution-reducing technologies. "Stronger co-operation between the two countries in energy and the environment," he wrote in the Financial Times on June 16, "will enable China to respond better to energy and environmental issues and also bring about tremendous business opportunities and handsome returns for American investors." In the careful language of one of China's top officials, this is an unexpected and welcome signal. The next administration should not ignore it. Vigorous follow-up would not only address one of the world's most pressing problems; it would also open up a new door for cooperation in the world's most important bilateral relationship.

AGREEMENTS AND DISAGREEMENTS

Given the dissatisfaction of Americans with the nation's present condition, it is hardly surprising that both Obama and McCain have sought to emphasize the changes they would bring. Both have said that they would put more emphasis on Afghanistan -- an early Bush administration success that has deteriorated dramatically as a result of neglect, miscalculation, and mismanagement. Both candidates have promised to strengthen U.S. relations with NATO allies. Both have expressed concern -- although in very different language -- over the recent behavior of Russia, especially in Georgia. (McCain has gone overboard, however, speaking in a highly confrontational manner and calling for the expulsion of Russia from the G-8, the group of highly industrialized states -- something that he surely knows would never be agreed to by the other six G-8 members and a bad idea in its own right.) Both have promised to rebuild the armed forces and take better care of the wounded from Afghanistan and Iraq. Both are committed to the support and defense of Israel. (Although both have said they would close down the detention facility at Guantánamo and ban torture, a significant difference emerged in a recent Senate vote: Obama supported, and McCain opposed, an important statutory requirement to hold the CIA to the same standards for interrogation as the military, as mandated in the U.S. Army Field Manual.)

It is the differences between Obama and McCain that are truly revealing, and they offer important insights into the values and styles of the two men, their profoundly divergent attitudes toward the role of diplomacy, and their contrasting visions for the United States. Obama's policy proposals -- whether on climate change, energy, Africa, Cuba, or Iran -- are forward-leaning; he proposes adjusting old and static policies to new and evolving realities. He emphasizes the need for diplomacy as the best way of enhancing U.S. power and influence. On trade, although McCain accuses Obama of neoprotectionism, in fact Obama argues for improving trade agreements to take into account elements such as labor and environmental standards -- improvements that would give them more domestic support.

In contrast, McCain's boldest proposals are neither new nor original: his vague "League of Democracies," for example, sounds like an expansion of an organization, the Community of Democracies, created by former Secretary of State Madeleine Albright that still exists but is virtually ignored by the current administration. Although McCain says his league "would not supplant the United Nations," he explicitly proposes that it take collective action when the UN does not. "The new League of Democracies," he said last year, ". . . could act where the UN fails to act, to relieve human suffering in places like Darfur [and] bring concerted pressure to bear on tyrants in Burma or Zimbabwe, with or without Moscow's and Beijing's approval." McCain calls this "the truest kind of realism." Whatever McCain says, his "League," unlike the forum created by Albright, would be viewed by everyone as an attempt to create a rival to the UN. Recent conversations I have had with senior officials in many of the world's leading democracies confirm that not even the United States' closest allies -- let alone the world's largest democracy, India -- would support a new organization with such a mandate.

The UN has been undermined and underfunded for the last eight years, often making it weaker and more vulnerable to anti-American positions. The UN is, to be sure, a flawed institution. But it plays an important role in U.S. foreign policy, and if correctly used, it can advance U.S. national interests and play a more effective role in peacekeeping in such difficult areas as Sudan. Yet the UN can only be as strong as its largest contributor (which is also a founding member), the United States, wants it to be. Obama would improve and reform the organization in ways that would serve the United States' interests, starting by asking Congress to pay the arrears that have grown once again, under Bush, to over $1 billion (an American debt of similar size was paid down after an arrangement made in the last year of the Clinton administration). Creating a new organization, instead of making a renewed effort at serious UN reform, would work against the very objectives McCain says he supports.

In his speech on nuclear proliferation delivered at the University of Denver on May 27, McCain said he would reconsider his long-standing opposition to the Comprehensive Nuclear Test Ban Treaty if a renegotiation could "overcome the shortcomings that prevented it from coming into force" -- a vague and elusive conditionality. Obama, in contrast, flatly favors this important treaty. Similarly, Obama has endorsed the goal of eliminating all nuclear weapons, as outlined in the now-famous article by former Secretary of State George Shultz, former Secretary of Defense William Perry, former Secretary of State Henry Kissinger, and former Senator Sam Nunn. McCain has pointedly refused to do so.

Looking at these and other differences, it is clear that the U.S. electorate is being offered two different visions of the United States' role in the world and two different attitudes toward diplomacy. On most issues, with the important exception of climate change, McCain supports or takes harder-line positions than the Bush administration. (For example, he expressed deep skepticism about the partial agreement President Bush announced in late June on the halting of North Korea's nuclear weapons development.) Although McCain prefers to describe himself as a "realist" or, more recently, a "realistic idealist," looking broadly at his positions, it is impossible to ignore the many striking parallels between him and the so-called neoconservatives (many of whom are vocal and visible supporters of his candidacy).

IRAQ AND IRAN

Of course, no disagreement between Obama and McCain reaches the level of importance of their disagreements over Iraq and Iran. Policy toward these two countries will shape perceptions of the new president more than policy on any other issue; in some ways, the election is a referendum on Iraq. When McCain says that the United States is in Iraq to win, he means it -- no matter what the costs or the duration of the war might be. No other issue engages him as deeply or as emotionally, and his feelings derive not from political calculation but from profound personal conviction. He believes that recent reductions in American and Iraqi casualty rates are proof that the United States is winning the war. As of this writing, however, he has not said that this highly welcome improvement in the situation would lead to significant troop withdrawals in 2009 beyond the removal of the "surge" troops whose departure has already been announced. He has repeatedly made clear that he is ready to leave troops in Iraq indefinitely rather than take the risks that he believes would accompany major reductions. He never acknowledges the risks and costs associated with continued deployments.

Obama, on the other hand, believes that military victory, as defined by Bush and McCain, is not possible -- a judgment shared by the U.S. commanders in Iraq. He finds unacceptable the costs to the United States of an open-ended commitment to continue a war that should never have been started. Obama concludes that in the overall interest of the United States, it is necessary to start withdrawing U.S. ground combat troops at a steady but, he emphasizes, "careful" pace. This will, he predicts, put far more pressure on Iraqi politicians to reach the compromises necessary to stabilize the country than leaving the troops there. Emphasizing diplomacy as an indispensable component of U.S. power, Obama has also called for an all-out effort to involve all of Iraq's neighbors in a regional diplomatic and political effort to stabilize the country.

McCain charges that his opponent's position (which he and his supporters often misrepresent as "precipitous withdrawal") would snatch defeat from the jaws of victory, encourage the United States' enemies, and weaken the nation. But he offers no exit strategy, no clear definition of achievable victory, and no plan for promoting political reconciliation within Iraq. His policy amounts to little more than a call for continuing the war because of the risks associated with trying to end it. Such a negative goal is not a sufficient rationale for putting still more American lives at risk.

Some of McCain's opponents have misstated, at times, his position on a key point: he never said that the United States might have to fight in Iraq for a hundred years. But what he did say was equally unrealistic and highly revealing of his mindset. Using as his model South Korea, where 28,500 American forces remain 55 years after the armistice agreement, McCain said that he was ready to station U.S. troops in Iraq for at least that long, if not longer, even a hundred years. Such a multidecade commitment, even under peaceful conditions, is inconceivable in the xenophobic and violent atmosphere of the Middle East. In the end, McCain defines every other issue in terms of Iraq. "Its outcome," he wrote in these pages late last year, "will touch every one of our citizens for years to come." That may be true, but perhaps not in the way that he intends.

Obama stands McCain's core argument on its head. "The morass in Iraq," he wrote, also in these pages, "has made it immeasurably harder to confront and work through the many other problems in the region -- and it has made many of those problems considerably more dangerous." Like McCain, who favored the war even before it began, Obama has been consistent: he opposed the war from its outset. He is well known, of course, for his intention to start withdrawing combat troops as soon as possible. But because he recognizes the complexities of withdrawal, he has also emphasized (to little press attention) the need to be extremely careful at every step of that process. Obama has said that he would maintain flexibility in regard to whether to leave a residual force and follow an exact timetable. "This redeployment," he wrote in these pages, "could be temporarily suspended if the Iraqi government meets the security, political, and economic benchmarks to which it has committed. But we must recognize that, in the end, only Iraqi leaders can bring real peace and stability to their country." He added, "The best chance we have to leave Iraq a better place is to pressure these warring parties [the Sunnis and the Shiites] to find a lasting political solution. And the only effective way to apply this pressure is to begin a phased withdrawal of U.S. forces."

The dispute between the Iraqi government and the Bush administration over a "status-of-forces agreement" highlights this issue. When the Iraqi prime minister insisted on a timetable for U.S. withdrawal (suggesting a three- to five-year adjustable schedule), why did both the current administration and McCain demure? Bush had often said that the United States would leave when it was not wanted; now he objects to a reasonable request from a sovereign state, seeming to prove the charge that the United States seeks a permanent presence in Iraq. Obama, on the other hand, calls it "an enormous opportunity . . . to begin the phased redeployment of combat troops." In July, reports surfaced that the administration might withdraw one to three combat brigades still in Iraq after the departure of the surge troops. If true, both candidates could claim they were right; Obama could plausibly say that this was what he had called for all along, and McCain could say that it justified his support for the surge.

At the heart of the United States' geostrategic challenge lie five countries with linked borders: the United States' NATO ally Turkey, Iraq, Iran, Afghanistan, and Pakistan. In this arc of crisis, incoherence has marked U.S. policy since 2003. This five-nation area falls into three different regional bureaus in the State Department. Washington preaches different policies on democracy in neighboring countries, confusing everyone -- pressuring Israel and the Palestinians, for example, into letting Hamas, the terrorist organization, run in the 2006 Palestinian elections, with disastrous results, while backing away from democracy promotion in Egypt. There is little coordination or integration of policies toward Afghanistan and Pakistan, although the two countries now constitute a single theater of war. No single concept beyond the vague "global war on terror" -- defined in any way that suits the short-term needs of the administration -- has guided U.S. strategy. Relations with all five countries have deteriorated.

Any serious policy will require dealing with all the countries in this region, as well as Israel and the Palestinian Authority, Lebanon, Syria, and Saudi Arabia. This unfortunately includes the very unpleasant reality at the center of this region, Iran. Both Obama and McCain agree that preventing Iran from becoming a nuclear weapons state must be a major priority. Both would tighten sanctions. Neither would remove the threat of the use of force from the table. But from that point on, their emphasis and language differ significantly. Obama has said repeatedly that he is ready to have direct contacts with Iran at whatever level he thinks would be productive, not only on nuclear issues but also on Afghanistan, Iraq, and Iran's support for terrorist organizations, including Hamas and Hezbollah (which Iran has equipped with tens of thousands of rockets aimed directly at Israel's heartland). McCain not only opposes such direct talks but also has famously said that the only thing worse than a war with Iran would be a nuclear Iran. Obama's forthright approach has been met with cries of alarm from McCain and his supporters, as though the very thought of talking to one's adversaries were in and of itself a sign of weakness, foreshadowing another Munich. This position is contradicted by decades of U.S. diplomacy with adversaries, through which U.S. leaders, backed by strength and power, reached agreements without weakening U.S. national security. Diplomacy is not appeasement. Winston Churchill knew this, Dwight Eisenhower knew it, and so did John F. Kennedy, Ronald Reagan, and George H. W. Bush.

This singular difference between Obama, on the one hand, and George W. Bush and McCain, on the other, offers an important insight into the underlying philosophies and values of the two candidates. Although McCain and his advisers have sometimes looked for ways to distance him from Bush, his position on Iran (as with Iraq) is tougher than that of the Bush administration. This is, one can safely assume, McCain's real view, which he sometimes expresses in pungent and humorous language ("Bomb, bomb, bomb, bomb, bomb Iran," he once sang at a public rally). Coupled with his criticism of the Bush administration's deal with North Korea and his call to throw Russia out of the G-8, his position suggests a deep, visceral aversion to talking to one's adversaries, perhaps stemming from a concern that such dialogue might be viewed as weakness. It also shows an innate skepticism of diplomacy as a frontline weapon in the United States' national security arsenal. Although both Bush and McCain attack Obama as weak, Obama's position is in fact closer to the traditional default position of almost everyone who has ever practiced or studied diplomacy or foreign policy. Even loyal pro-McCain Republicans, such as James Baker, Robert Gates (before he became secretary of defense), Henry Kissinger, and Brent Scowcroft have disagreed with the McCain position on Iran and Russia.

Of course, there is no certainty that serious talks are possible with the real power center of Iran: Supreme Leader Ayatollah Ali Khamenei and his inner circle. It is therefore important, before starting down the diplomatic track, to have a clear idea as to what should be done if talks either are refused or make no progress. Contacts should begin through private and highly confidential channels to determine if there is a basis on which to proceed. The ongoing low-level communication through the U.S. and Iranian embassies in Baghdad, although limited in scope and unproductive so far, could allow for initial probing with little risk of compromise, and there are several ongoing private "track-two" efforts that could also be useful. The model that comes to mind, not surprisingly, is the one that President Richard Nixon and his national security adviser, Kissinger, used to open a dialogue with China in 1971, after 22 years of noncontact. Nixon's decision to talk to one of the most repressive regimes in the world, at the height of the insanity of the Cultural Revolution, came at a time when Beijing's treatment of its own population was certainly worse than that of Tehran today. China was also supporting guerrillas fighting U.S. troops in Southeast Asia. Yet Nixon and Kissinger talked to Mao Zedong -- and changed the world. (The way not to proceed is to emulate Reagan's move in 1987, at the height of the Iran-contra drama, when he secretly dispatched his national security adviser, Robert McFarlane, to Tehran carrying a chocolate cake decorated with icing in the shape of a key.)

Would an effort at dialogue with Iran produce results? Could it reduce the overt anti-Israel activities of the Iranian government, which poses an existential threat to the Jewish state? Could it stop the Iranian nuclear program? Is there enough common ground to enlist Iran in a regional project to stabilize Iraq and Afghanistan? None of these questions can be answered in advance, but most scholars and experts believe that there are sufficient parallel interests to make the option worth exploring, just as Obama (and all the other candidates for the Democratic nomination) has suggested. Combined with the threat of tougher sanctions -- and with the use of force remaining on the table -- this carrot-and-stick approach would not threaten the security of either Israel or the United States, and it would strengthen the United States' position elsewhere in the world, especially with other Muslim states, regardless of its outcome.

If Tehran rebuffs an opportunity to have meaningful talks with Washington, it will increase its own isolation and put itself under greater international pressure, while the United States will improve its own standing. Of course, this journey, once begun, will require adjustments along the way. Diplomacy is like jazz -- an improvisation on a theme. Let it begin next year, as part of a new foreign policy in which diplomacy, conducted with firmness and enhanced by U.S. power, and consistent with American values, returns to its traditional place in the United States' national security policy.

Such an approach toward Iran, coupled with the drawdown of U.S. combat units in Iraq, would have an important additional benefit: it would enhance the value of a return by the United States to its role as a serious, active peacemaker between the Israelis and the Palestinians. As with so many other issues, the Bush administration wasted most of its eight years not attending to this one, only finally engaging with it in 2007, with the "Annapolis process" launched by Secretary of State Condoleezza Rice. That effort will not lead to anything more than, at best, a loose framework agreement before the administration's time runs out. The next president must engage personally with this issue, as every president from Nixon to Bill Clinton has in the past.

THE OTHER WAR

Although both Obama and McCain agree on the importance of the "other war" -- that in Afghanistan -- this alone is not sufficient. Current U.S. policy in Afghanistan is a failure. American voters should hear in more detail what each candidate would do about it. For McCain, the question arises as to where the additional resources needed would come from if he continues the war in Iraq. Obama has already pledged at least 10,000 more troops.

Since the U.S.-led coalition's initial success in driving the Taliban from the cities, the basic U.S. plan and timetable in Afghanistan have been upended time and again by events that were not foreseen and policies that were inept. This past year, disaster was staved off only with the dispatch of additional British, Canadian, French, and U.S. troops. The right course now does not lie in a huge increase in NATO forces, although additional forces will be required for the southern and eastern parts of the country. The Taliban cannot win in Afghanistan; their terror tactics and memories of the "black years" repel most Afghans. But by not losing, by staying alive and causing continual trouble, the Taliban are achieving a major objective -- preventing success by the central government, tying down large numbers of NATO troops, rallying "jihadists" from around the world to a remote but oddly romantic front. Faced with this challenge, the central government has shown that it is simply not up to the job. Meanwhile, the international community, a vast and uncoordinated collection of nongovernmental organizations, international agencies, and bilateral organizations, does enormous good but, paradoxically, sometimes undercuts its own goals by creating an ever-deeper dependency on foreigners for services that Kabul cannot deliver.

The situation in Afghanistan is far from hopeless. But as the war enters its eighth year, Americans should be told the truth: it will last a long time -- longer than the United States' longest war to date, the 14-year conflict (1961-75) in Vietnam. Success will require new policies with regard to four major problem areas: the tribal areas in Pakistan, the drug lords who dominate the Afghan system, the national police, and the incompetence and corruption of the Afghan government. All present immensely difficult challenges, but the toughest is the insurgent sanctuaries in the tribal areas of western Pakistan. Afghanistan's future cannot be secured by a counterinsurgency effort alone; it will also require regional agreements that give Afghanistan's neighbors a stake in the settlement. That includes Iran -- as well as China, India, and Russia. But the most important neighbor is, of course, Pakistan, which can destabilize Afghanistan at will -- and has. Getting policy toward Islamabad right will be absolutely critical for the next administration -- and very difficult. The continued deterioration of the tribal areas poses a threat not only to Afghanistan but also to Pakistan's new secular democracy, and it presents the next president with an extraordinary challenge. As a recent New York Times article stated, "It is increasingly clear that the Bush administration will leave office with Al Qaeda having successfully relocated its base from Afghanistan to Pakistan's tribal areas, where it has rebuilt much of its ability to attack from the region and broadcast its messages to militants across the world." Nothing -- not even Iraq -- represents a greater policy failure for the outgoing administration.

AN OVERFLOWING AGENDA

The focus here on a few major issues does not mean that others can be ignored. If history is any guide, issues that are neglected too long often emerge at the top of the policy agenda -- Somalia, Bosnia, Cambodia, Darfur, Myanmar (also known as Burma), Tibet, and Zimbabwe are only a few recent examples. So even as a new administration starts to deal with the arc of crisis, it must also pay close attention to issues that could easily overwhelm it, in much the way Rwanda did Clinton's administration in 1994, when the president's focus was on Bosnia. A good example is Sudan, where, in addition to there being a deepening crisis in Darfur, the North-South agreement, once hailed as a genuine Bush-era success, is now in danger of collapse. It is likely that its key provision (national elections followed by a referendum on independence in the South) will be ignored or repudiated. By 2010, the odds are that Sudan will once again explode into a major North-South conflict, with the perennial risk of involvement by its neighbors. Preventing such a scenario will take intense efforts, led by the United States and the Africa Union and requiring the active involvement and support of China.

U.S. relations with the Muslim world will require special attention; efforts so far to encourage moderate Muslims to deal with extremists have not worked. A new, creative approach to public diplomacy must be developed. Then there is the odd problem posed by the "democracy agenda" of the last six years. The Bush administration's inept advocacy of a fundamental human right has contaminated one of the nation's most sacred concepts. Bush did the dream of democracy a huge disservice by linking it to the assertion of U.S. military power. Pressuring other countries to adopt the superficial aspects of a complex and subtle system of governance is simply not the route to follow in promoting American values or security interests. Yet the goal is correct and should not be abandoned -- only presented in a style and a tone far more sensitive to how it is perceived in other lands. The next administration should focus more on human rights (a phrase curiously absent from the Bush lexicon) and basic human needs while still encouraging the development of democratic forms of government, accompanied by the evolution of a pluralist political culture, the rule of law, and improvements in material conditions, especially through job creation. If there is progress in these areas, democracy will follow, in ways that countries will determine for themselves -- with U.S. encouragement. That is the lesson of Chile, Indonesia, the Philippines, South Korea, Taiwan, and several promising young democracies in Africa.

It was in Africa that President Bush produced his greatest success -- his anti-AIDS program, one of the few bipartisan policies of the last eight years. The United States has spent over $13 billion on the program since 2003. It has saved well over one million lives so far and incentivized other nations to do more. But the Bush administration's Africa policy has been notably deficient in addressing the strategic, economic, and environmental dimensions of Africa's plight. It has failed to deploy the instruments of statecraft in addressing Africa's debilitating cycle of violence -- in the Democratic Republic of the Congo, Sudan, Zimbabwe, and the obscure but explosive Horn of Africa. The world needs a strategy to address Africa's endless conflicts, and that strategy must include a political approach to conflict resolution. The next administration must attend to the crises and mobilize support from its allies and from the African Union. The Bush administration played a useful role during the postelection crisis in Kenya (as did Obama, who gave interviews to Kenyan media and the Voice of America), but nowhere else on the continent has the United States been particularly effective. The UN is a key player, but the United States must lead the effort to get more resources for UN peacekeeping in Africa, or else such efforts will have no chance of success. In Obama's extraordinary trip to Africa in 2006, he gave early hints of the promise of his candidacy. When I visited Kenya a few months later, I felt the excitement that his visit, including his undergoing a public HIV test in Nairobi, had generated. The conventional wisdom on Africa is that it is a hopeless case. This view -- which amounts to triage by continent -- is neither true nor acceptable morally, politically, or strategically.

In Latin America, the United States must begin to redress the widespread skepticism toward U.S. leadership -- but not by making implausible promises to eradicate poverty and inequality or to stop drug trafficking and rampant crime. The greatest boost the next president can give to the realization of the long-elusive consolidation of a social contract in Latin America starts with recovering the social contract at home. Immigration reform and policies to alleviate economic anxiety, from introducing universal health care to making major investments in education and infrastructure, will create the surest path to rebuilding U.S. public support for what is now de facto integration with Latin America, whether through capital or language, commerce or culture.

To advance U.S. interests, Washington needs a different relationship with Mexico and strategic ties with Brazil. In Mexico's case, thriving trade along a 2,000-mile border, vast population networks, and shared vulnerability to increasingly pervasive organized-crime syndicates require sustained presidential attention, as Bush promised but was unable to deliver. In Brazil -- the world's ninth-largest economy, a leading global producer of food and ethanol, an emerging petroleum giant, a potential nuclear power, and a major emitter of greenhouse gases -- the next president can find a partner to advance key global initiatives, help define the shape of multilateral institutions, and act as a diplomatic ally in confronting the toughest regional challenges.

LEADING IN A MULTIPOLAR WORLD

The United States is not a helpless giant tossed on the seas of history. It is still the most powerful nation on earth, and within certain limits, it can still shape its own destiny and play the leading role in a multipolar world. It can still take the helm in addressing the world's most pressing problems (as President Bush did effectively on only one issue, AIDS). There are many issues waiting for inspired and, yes, noble U.S. leadership, backed up by enlightened U.S. generosity that is also in the United States' own interest. The United States is still great. It deserves leadership worthy of its people, leadership that will restore the nation's pride and sense of purpose. That task must begin at home, but the world will be watching and waiting.

ONCE IN OFFICE . . .

It is a well-established historical fact that what candidates say about foreign policy is not always an exact guide to what they will do if elected. Historians point to a myriad of examples: Franklin Roosevelt's 1940 promise to not send "your boys . . . into any foreign wars," Lyndon Johnson's statements in 1964 that he would not send ground troops to Vietnam, Richard Nixon's 1968 references to a nonexistent "secret plan" to get out of Vietnam, Ronald Reagan's 1980 pledge to upgrade U.S. relations with Taiwan to "official" status, Bill Clinton's 1992 promises to take a strong stand on Bosnia and stand up to the "butchers of Beijing," George W. Bush's 2000 call for a "more humble" foreign policy that would never again have the United States involved in "nation building." If a candidate takes a position that, on reaching the White House, he concludes is wrong, it obviously would be irresponsible to stick with that position; national interest must take precedence over statements made in the heat of a campaign. However, reversals of campaign positions, no matter how necessary, are painful for any politician and certain to be used against him by his opponents regardless of the circumstances. (A memorable experience for me involved Jimmy Carter's 1976 campaign pledge to withdraw all U.S. ground troops from South Korea, a pledge he reaffirmed publicly shortly after the election. I had argued against it, but as Carter's assistant secretary of state for East Asian and Pacific affairs, I then had to defend it publicly while, under the direction of Secretary of State Cyrus Vance and Secretary of Defense Harold Brown, working to reverse it as quietly as possible -- which was finally done, after two difficult years, in the summer of 1979.) Whatever their ultimate fate, however, campaign positions are key indicators of the priorities and thinking of each candidate as he approaches the most powerful and difficult job in the world. It is therefore valuable to examine them carefully.

Richard Holbrooke was U.S. Ambassador to the United Nations from 1999 to 2001 and chief architect of the 1995 Dayton peace agreement. He is currently Chair of Asia Society.