When prominent people in Washington spend an anniversary apologizing for being catastrophically, unforgivably wrong about a decade-old decision, you might expect that the decision in question had delivered their party to disaster or defeat. But last week's many Iraq war mea culpas were rich in irony: One by one, prominent liberals lined up to apologize for supporting a war that's responsible for liberalism's current political and cultural ascendance.
History is too contingent to say that, had there been no Iraq invasion in 2003, there would be no Democratic majority in 2012. (It's easy enough to imagine counterfactuals that might have put Hillary Clinton in the Oval Office.) But the Democratic majority that we do have is a majority that the Iraq war created: Its energy and strategies, its leadership and policy goals, and even its cultural advantages were forged in the backlash against George W. Bush's Middle East policies.
All those now-apologetic liberals who supported the war in 2003 are a big part of this story, because without their hawkishness there would have been no anti-war rebellion on the left -- no Michael Moore and Howard Dean, no Daily Kos and all its "netroots" imitators.
This rebellion divided the Democrats, but it also energized them. During the long Reagan era, American liberalism was an ossified establishment pitted against a successful right-wing insurgency. But the anti-Iraq war insurgency created something new in modern politics -- a kind of "movement liberalism" that thought of itself in the same scrappy, ideologically driven terms as the conservative movement, and that was determined to imitate conservatism's tactics, institutions and success.
Had the Iraq invasion turned out differently, this movement and the Democratic establishment might have spent a decade locked in conflict. But when the weapons of mass destruction didn't turn up and the occupation turned into a fiasco, the two wings of the party made peace: The establishment embraced the grass roots' anti-Bush fervor, and the insurgents helped transform liberalism's infrastructure and organizing and communication.
This synthesis was then solidified by the Obama campaign. Barack Obama the candidate convinced both the insurgents (who originally preferred John Edwards) and the Hillary-favoring establishment that he was one of them, and his team leveraged grass-roots enthusiasm and online savvy to build the juggernaut that won in 2008 and 2012.
But Obama didn't just benefit from the zeal that entered the Democratic Party through the anti-war movement; he also benefited from the domestic policy vacuum left by Bush's Iraq-ruined second term. The Bush White House's "compassionate conservatism" was the last major Republican attempt to claim the political center -- to balance traditional conservative goals on taxes and entitlement reform with more bipartisan appeals on education, health care, immigration and poverty. And as long as the Republican Party was successfully hovering near the middle, the Democrats had to hover there as well.
But once Bush's foreign policy credibility collapsed, his domestic political capital collapsed as well: Moderates stopped working with him, conservatives rebelled and the White House's planned second-term agenda -- Social Security reform, tax and health care reform, immigration overhaul -- never happened.
This collapse, and the Republican Party's failure to recover from it, enabled the Democrats to not only seize the center but to push it leftward, and advance far bolder proposals than either Al Gore or John Kerry had dared to offer. The Iraq war didn't just make Obama possible -- it made Obamacare possible as well.
Nor is it a coincidence that these liberal policy victories have been accompanied by liberal gains in the culture wars. True, there's no necessary connection between the Bush administration's Iraq floundering and, say, the right's setbacks in the gay-marriage debate. But cultural change is a complicated thing, built on narratives and symbols and intuitive leaps.
As The American Conservative's Dan McCarthy noted in a shrewd essay, the Vietnam War helped entrench a narrative in which liberal social movements were associated with defeat in Indochina -- and this association didn't have to be perfectly fair to be politically and culturally potent.
In a similar way, even though Donald Rumsfeld and Dick Cheney weren't culture warriors or evangelical Christians, in the popular imagination their legacy of incompetence has become a reason to reject social conservatism as well. Just as the post-Vietnam Democrats came to be regarded as incompetent, wimpy and dangerously radical all at once, since 2004 the Bush administration's blunders -- the missing WMD, the botched occupation -- have been woven into a larger story about Youth and Science and Reason and Diversity triumphing over Old White Male Faith-Based Cluelessness.
Of all the Iraq war's consequences for our politics, it's this narrative that may be the war's most lasting legacy, and the most difficult for conservatives to overcome.
Ross Douthat is a columnist for The New York Times.
By ROSS DOUTHAT