Now that Obama has the nomination locked up, people are starting to take a look back at the past few months to figure out how he pulled off one of the biggest upsets in modern political history. The Clintons were thought to have the most formidable political machine in the country, and 17 months ago Obama started with nothing.

How'd he do it? For one, he out organized her. Clinton staffed her campaign with loyalists who bought into the idea of her inevitability. (Remember the media narrative last year? Even Republicans were ready to declare Hillary the next president). While Obama's team mapped out every delegate, built a monster grassroots network, and broke online fund raising records, the Clinton team failed to plan beyond Super Tuesday and had a poor grasp of the primary rules. So instead of playing to the rules, they were forced to constantly redefine them.

But that's not ultimately why Obama pulled this off. She had a chance to win this election in 2002. Even if he had run a flawless campaign and she had committed many of the same errors, if Hillary Clinton had voted against the authorization to use force in Iraq, Obama would not be in the position he's in today. He probably wouldn't have entered the race. She might not have stopped the war with her vote, but as the Senate's biggest celebrity at the time, her leadership would have made a world of difference.

Not only did she vote for the war, but she refused to apologize for the vote or acknowledge the error during her campaign. “If the most important thing to any of you is choosing someone who did not cast a vote [to authorize the war] or has said his vote was a mistake, then there are others to choose from,” she told voters for New Hampshire. For a lot of voters, including myself, that was the most important thing. Even if you give her the benefit of the doubt on her claim that she was misled into war by faulty intelligence (even though she supposedly didn't read the National Intelligence Estimate before voting), her failure to acknowledge that it was a mistake is tough to look past.

She could have prevented this, but like other Democratic senators who later became contenders for the presidency (John Kerry, John Edwards, Chris Dodd, Joe Biden), she made a mistake that we're still paying for five years later. Did their presidential aspirations influence these senators to vote for what seemed to be a popular war at the time? The cynic in me says yes, but that's just speculation. At best, they allowed the administration to play the classic Democrats-are-weak-on-national-security card and failed to show backbone or leadership.

As Matthew Yglesias and Atrios have pointed out today, the influence of Clinton's 2002 vote is being lost in the analyses of her campaign. It's not surprising that pundits and journalists are still caught up in the horse race politics of the last few months, but the influence of the war in this outcome should not be overlooked or forgotten.

This time we will not be forced to choose between a Republican who supported the war and a Democrat who supported, and then changed his/her mind. Every Democrat who initially supported the war and has since sought the presidency has lost. That's a message to Hillary Clinton that maybe apologizing for a mistake isn't always a bad thing. And it's a message to the party known for its spinelessness that it's time to finally grow a spine and stop making decisions based on emasculating taunts from Republican.

And if/when Obama is elected in November, it ultimately won't be because McCain is older than dirt, or because his speeches are about as entertaining as a root canal, or because of the candidates' respective debate performances and gaffes. It'll be because of the war.