To the credit of Christopher Layne, a professor at Texas A&M's Bush School of Government and Public Service, and Bradley Thayer, a professor of strategic studies at Missouri State, they have set out to do their part in correcting that problem when it comes to America's grand strategy with American Empire: A Debate.

As the title indicates, Thayer and Layne lay out, respectively, arguments for and against a U.S. foreign policy whose explicit goal is maintaining American primacy on the world stage--what both call the "American Empire." Layne and Thayer are professed realists; so having power, keeping it, and using it wisely are the key ingredients of this debate. What divides the two is their estimation of the costs and benefits of a grand strategy that rests on American global hegemony.

Thayer opens the book with his case for American primacy, arguing that, indeed, America is an empire, but not a traditional one: Its influence is now mostly tied to the indirect sway and security provided by its military power, its economic muscle, and the soft power associated with its political ideals and its dominating cultural presence around the globe. Moreover, the spirit behind America's empire is the "spirit of 1776." From the get-go, Americans wanted to expand geographically and, equally important, saw their notions of political and economic freedom as "a light to the nations." In its bones, America was never a status quo power.

While Layne's preferred strategy of sitting above the world's fray is not likely to fit well with the universalistic character of American liberalism, Thayer's problem is sustaining his strategy in the face of the other side of American liberalism, with its decided focus on the pursuit of happiness.

Yet, even if America has a hegemonic instinct, Thayer reasonably asks: Can the country pull it off? Can the United States retain its primacy, or will other powers, as most realists believe, react to such overwhelming power by challenging it? Of the available candidates for doing so--China, Europe, and radical Islam--only China presents a significant problem, according to Thayer. Europe is dying away; terrorism is a bloody nuisance but manageable--even China's longer-term prospects are iffy given its own internal problems.

And, of course, even if the United States can pull it off, should it? Here Thayer argues that, absent another realistic alternative to keep peace and stability in the world, it remains in America's interest to play the role of hegemon. It might not make us loved, but the general stability provided by the American security umbrella of alliances and forces has made the world a lot more peaceful than it otherwise would be.

For reasons of economics and the broad state of humanity, that is a pretty good return on the money.

Layne's argument is that there is, in fact, a realist's alternative to the endless pursuit of primacy: a strategy of "off-shore balancing" that amounts to a quasi-isolationist policy of selective diplomatic and military engagement. And indeed, the "offensive" realist's argument for primacy rests, Layne suggests, on paying too much attention to the lessons supposedly learned from the security problems and strategies for dealing with them that arose from centuries of competition among the powers of continental Europe. Given America's geography and weak neighbors, the security model that is far more relevant to our situation is the one adopted by maritime Britain: a small army, a big fleet, and a willingness to be quick on one's feet when it comes to finding new allies and dumping old ones.

Today's primacy advocates couple it with a policy of promoting democracy, believing that the world is a safer place when there are more democracies, not less--a thesis Layne calls the most "over-hyped and under-supported theory ever to be concocted by American academics."

According to Layne, the advantage of his alternative grand strategy is that it avoids stimulating great power rivalries, eliminates the economically disastrous consequences of "imperial overstretch," and precludes the necessity of a "national security state" in which our rights and civic culture are put at risk. Finally, it avoids the mess (e.g., Somalia and Iraq) of democracy promotion and nation-building.

American Empire concludes with brief responses by Thayer and Layne to each other's arguments, flushing out their original positions and critiques.

Specialists in the field of international security will quibble that Thayer and Layne's two grand strategies are not the sum total of grand strategies available to the American "empire." Nor will they be satisfied with the somewhat loose way in which the term "empire" is used by both authors. That both authors admit the United States is not an empire in the traditional sense seems to suggest that it isn't, in fact, an empire: Hegemony and empire are not one and the same, although admittedly their attributes can at times overlap. That said, the book does provide plenty of material for thought and, more important, debate.

The biggest problem, however, lies in Christopher Layne's dyspeptic analysis of current policy opponents. Rather than taking the opposing argument as seriously as Thayer takes his, Layne resorts to unsubstantiated claims about "neocons," the White House lying, and small cabals (the so-called "Blue Team") trying to foment a "preventive" war with China. Similarly, his dismissal of the democratic peace theory is equally over-the-top. Even if one thinks that the theory is, at times, oversold, to claim that it has absolutely no merits is bound to leave most readers with the sense that there is as much anger as argument in the case Layne is making.

An additional problem, perhaps tied to the way the book is structured, is that Layne spends the vast majority of his time criticizing the argument for primacy, without giving the reader much of a handle on his own preferred strategy's particulars. As a result, we don't know whether his model of "off-shore balancing" is more British in style--that is, fairly active in playing the decisive power broker among the other competing states--or more passive in content--a la the United States in the 1920s and '30s.

If the former, a key problem with the strategy is that it requires a far more calculating style of statecraft than the United States has ever engaged in before. And even if we had Henry Kissinger upon Henry Kissinger to carry it out, would the American public really be willing to let its government play this version of international politics--shifting partners based on power relations--rather than the character of the states themselves? Surely, the disappearance of the United States as security guarantor is likely to lead to more competition among states and the creation of a more chaotic and fluid international environment. Britain had a hard enough time playing this role in its day, and found itself in numerous conflicts in any case.

If the latter, the passive "off-shore balancing" approach leads to the question of whether such a strategy results in the United States addressing a security problem at a time when it may be far more difficult to deal with. Layne's bet, at least in the case of Iran and China today, is that if the United States would only get out of the way, other powers would naturally begin to meet their challenge. Possibly. But doing so might create an even more destabilizing competition among neighbors, or lead those same neighbors to accept China or Iran's new hegemony, fueling their ambitions rather than lessening them.

The history of international relations suggests that most great crises are the result of not addressing more minor ones initially. As Thayer argues, it is probably less costly to deal with these issues when one is in a better position to do so than to wait for them to become full-blown security problems.

And speaking of money: Layne's argument about looming imperial overstretch is itself a stretch. Even with all the problems in Iraq, a war in Afghanistan, and an emerging hedging strategy vis-a-vis China, the defense burden is still barely over 4 percent of the country's gross domestic product. The United States has certainly had far higher defense burdens in the past, while still retaining its status as the world's economic juggernaut. There may be plenty of reasons to worry about the country's economy, but "guns over butter" is hardly one of them.

Moreover, while pulling back from a forward-leaning defense strategy would undoubtedly save money, offshore balancing would still require the United States to have a major military establishment in reserve if it wanted to be capable of being a decisive player in a game of great power balancing. Is the $100 billion or so saved--or, rather, spent by Congress on "bridges to nowhere"--really worth the loss in global influence that comes from adopting Layne's strategy?

As someone who has been called a neoconservative, I suppose one would expect me to read Thayer's argument in a more friendly light--which I do. Nevertheless, his presentation suffers from its own problems.

First, in response to Layne's argument that Iraq has been an unmitigated disaster, Thayer tries too hard to put a happy face on the problem. The reality is, a strategy of primacy doesn't rest on success in Iraq. It may tell us how prepared or unprepared we are as a government for that role, but it doesn't necessarily vitiate the strategy's general validity. That said, having a strategy dedicated to maintaining primacy does, in fact, put a premium on preemption--not necessarily or even primarily military preemption, but certainly a strong impetus to use all the tools of statecraft to shape both the security environment and other states' behavior. As such, it is an inherently active and somewhat openended strategy that requires heading off challenges before they become threatening ones.

Obviously, that can lead to misjudgments about what really needs doing and what only appears to need doing. But that is less a problem--since it is no less a problem for those who want to engage in balance-of-power politics--than the fact that the American public is not especially willing to dedicate significant treasure or blood to deal with threats that are over the horizon. As someone who argued that there was a remarkable strategic opportunity available to the United States and its democratic allies in the wake of the Soviet empire's collapse, I can honestly say that, until the attacks of 9/11, the post-Cold War public was hardly seized with a determination to make the most of that opportunity.

So, while Layne's preferred strategy of sitting above the world's fray is not likely to fit well with the universalistic character of American liberalism, Thayer's problem is sustaining his strategy in the face of the other side of American liberalism, with its decided focus on the pursuit of happiness. Contrary to what Layne imagines, the issue of sustainability is not one of material resources, or even the rise of great power competitors supposedly generated as a response to U.S. primacy. As Thayer notes, America has never been more powerful, and never has a country been able to call so many of the nations of the world friends or allies. No, the real issue is public will and the quality of leadership necessary to sustain that will in the face of both difficulties, and the enervating consequences of primacy's own success.

Gary J. Schmitt is director of the Program on Advanced Strategic Studies and a resident scholar at AEI.