Why did a majority of Democratic senators — such as Joe Biden, Hillary Clinton, Chris Dodd, John Edwards, Harry Reid, Jay Rockefeller and Chuck Schumer — vote to authorize a war with Iraq on Oct. 11, 2002? And why is this war now supposedly George Bush's misfortune and not theirs?

The original fear of Iraqi weapons of mass destruction, of course, played a role in their votes — but only a role. In the 23 writs that authorized force to remove Saddam, senators at the time also cited Iraq's sanctuary and subsidies for terrorists. Then there were Saddam's attempts to assassinate a former U.S. president; his repression of, and use of weapons of mass destruction against, his own people; and his serial violations of both United Nations and Gulf War agreements. If paranoia over weapons of mass destruction later proved just that, these other more numerous reasons to remove Saddam remain unassailable.

Nevada's Sen. Reid summed up best the feeling of Democrats that there were plenty of reasons to remove Saddam Hussein in a post-9/11 climate. He reminded his Senate colleagues that Saddam's refusal to honor past agreements "constitutes a breach of the armistice which renders it void and justifies resumption of the armed conflict."

But it was not just fear of Saddam alone that prompted Democrats to authorize the use of force to remove him. There was the more general, liberal notion of using American arms to stop violent dictators. While the Democratic Party has a strong pacifist wing, its mainstream has always advocated a global promotion of American liberal values — sometimes through the use of preemptory force.

Many Democrats in Congress, for example, had earlier authorized George Bush Sr. to fight the first Gulf War to stop Saddam's mad drive to absorb Kuwait. In 1999, House Democrats sought, but failed, to pass congressional authorization for President Clinton's ongoing air war against Slobodan Milosevic.

Democratic leaders from Bill Clinton to Barack Obama have long lamented that the United States did not preempt in Africa to stop the Rwandan genocide. In contrast, George Bush, not Al Gore, ran for the presidency in 2000 promising to end Clinton's humanitarian interventions, whether in the Balkans, Haiti or Somalia. As then-candidate Bush put it, "I don't think our troops ought to be used for what's called nation-building."

Throughout American history, it was usually the Democratic Party that proved the more interventionist. Democratic presidents — whether Woodrow Wilson in 1917, Franklin Delano Roosevelt in 1939-40, Harry Truman in 1950, John Kennedy in 1963 or Bill Clinton in 1999 — long battled Republican isolationists who insisted that it was never in America's interest to fight costly wars abroad unless directly attacked by a foreign nation.

Again, why then did the majority of Democratic senators vote for the present war in October 2002?

One, they rightly concurred with the president's post-9/11 conversion to the idea that removing a Middle Eastern mass-murdering regime and leaving a consensual government in its place could be a key component in winning the war against Islamic terrorism. And two, their party had always believed that the United States can sometimes make things better abroad by stopping tyrants and dictators.

By the same token, why do many of these same initial supporters of the Iraq war four years later now promise either to withdraw troops or to cut off funds, and so often hedge on or renounce their past records?

Partisan advantage explains much of the present posturing against an opposition president. But mostly, the rising Democratic furor comes as a reflection of public anger at the costs of the war — and the sense that we are not winning.

Unlike the invasion of Panama (1989), the Gulf war (1991), the Balkans war (1999) or even the Afghanistan conflict (2001-2007), Iraq has taken more than 3,000 American lives. Had the reconstruction of Iraq gone as relatively smoothly as the three-week removal of Saddam, most Democratic candidates would now be heralding their past muscular support for democratic change in Iraq.

So instead of self-serving attacks on the present administration, Democratic senators and candidates should simply confess that while most of the earlier reasons to remove Saddam remain valid, the largely unforeseen costs of stabilizing Iraq in their view have proved too high, and now outweigh the dangers of leaving.

But they should remember one final consideration. The next time a Democratic administration makes a case for using America's overwhelming military force to preempt a Milosevic or a mass murderer in Darfur — and history suggests that one will — the Democrats' own present disingenuous anti-war rhetoric may come back to haunt them, ensuring that such future humanitarian calls will probably fall on ears as deaf as they are partisan.

Victor Davis Hanson is a classicist and historian at the Hoover Institution at Stanford University. Reach him at author@victorhanson.com.