The history I have in mind is 1972. By the end of that year, 56,844 Americans had been killed in Vietnam, a war that almost no one thought could still be won and which no one could quite figure out how to end. Nevertheless, the winner in that year's presidential election was Richard M. Nixon. He won 49 of 50 states -- and the war, of course, went on.

Just as it is hard to understand how the British ousted Winston Churchill after he had led them to victory in Europe in World War II, so it may be hard now to appreciate how Nixon won such a landslide while presiding over such a dismal war. In the first place, he was the incumbent, with all its advantages, and with enormous amounts of money at his disposal. In the second place, back then the Vietnam War was not as unpopular as you might think -- or, for that matter, as the Iraq War now is. In 1972, almost 60 percent of Americans approved the way Nixon was handling the war.

Maybe more to the point, most Americans did not endorse the way the Democrats would handle the war -- nor the way the anti-war movement was behaving. Nixon seized on those sentiments and, in a feat that historians will be challenged to explain, characterized George McGovern as something of a sissy. In fact, the Democratic presidential nominee was a genuine World War II hero, a B-24 pilot with 35 combat missions under his belt and a Distinguished Flying Cross on his chest. Nixon, in contrast, had served during the war but never saw combat. He had, however, seen the polls.

This is similar to what happened in the 2004 campaign. The George Bush-Dick Cheney ticket consisted of two Vietnam slackers. Bush had served in the Air National Guard and Cheney had obtained five draft deferments. Their opponent was the much-decorated John Kerry -- Silver Star, Bronze Star and three Purple Hearts. Yet during the campaign, the Republican ticket and its allies in the Swift Boat Veterans movement managed to paint Kerry as a quivering liar. The character attack was so bold, so outrageous, that it of course worked.

Now we come to the current race. The war in Iraq is not -- or not yet -- an issue for Republicans. With the exception of Ron Paul, they all more or less support the president. It is among the Democrats that the war is a divisive issue -- John Edwards sniping at Hillary Clinton and Barack Obama, and Obama sniping at both. Everyone now opposes the war, but the issue is not so much their positions as much as the intensity of their feelings. Anti-war Democrats in key primary and caucus states, particularly New Hampshire and Iowa, will not vote for a lukewarm anti-war candidate. This accounts for why Clinton recently reversed herself and voted to end funding for the war. The one presidential candidate from the Senate who did not was Joseph Biden. He said he opposed the war but saw no choice but to fund the troops.

Precisely right, Joe. But more than right, prescient as well. As if to suggest what an issue this will become, Rudolph Giuliani called Clinton's vote a "significant flip-flop.'' Since then the Republicans have mostly trained their fire on each other. You can bet, though, that if Clinton gets the nomination, this vote will be hung around her neck and the hoariest of cliches will be trotted out: weak on defense. It will have added resonance because Clinton is a woman.

This is where history raises it ugly head. The GOP is adept at painting Democrats as soft on national security. It is equally adept at saying so in the most scurrilous way. And while most Americans would like the war to end, they do not favor a precipitous withdrawal and neither have they forgotten Sept. 11, 2001 -- the entirety of Giuliani's case for the presidency, after all.

Will History trump the polls? It will, if as in the past, the Democratic Party so wounds itself fighting the war against the war, it nominates a candidate beloved by a minority but mistrusted by a majority. It has happened before.