Musing on what might have been if Al Gore had won Florida in 2000 - namely, a Democratic Party rallying around a presidential nominee named Joe Lieberman in 2008 - Yglesias throws in this curveball:

And of course there's also a universe in which John McCain accepted John Kerry's offer of the VP slot, and the two of them ran and won a bipartisan ticket committed to ending the incompetence of the Bush administration and prosecuting the war in Iraq the right way. That world would likely have involved a "troop surge" and reliance on the sort of counterinsurgency theories associated with David Petraeus (who, at the time, was a favorite of Bush-critical journalists).

The obvious Kerry foreign-policy counterfactual, to my mind, involves some half-hearted attempts at counterinsurgency followed by a Baker-Hamilton style exit strategy for Iraq starting in mid-2006 or so. But of course it's easy to forget about the bizarre but real possibility of a Kerry Administration with John McCain as its foreign-policy czar, which might well have produced a turn to a surge-style strategy much, much sooner than the surge we actually got. With Bush out of the picture, the GOP would have held on to Congress in 2006, and thanks to security gains in Iraq, Kerry would have been cruising to re-election in his all-Massachusetts matchup against Mitt Romney this year -  until the economic crash (what, you think a President Kerry would have prevented it?) suddenly produced a massive tightening in the polls, as the Democratic ticket's foreign policy edge (a vote for Kerry-McCain is a vote for victory!) was undercut by Romney's sudden lead on economic issues, built on extremely effective ads tying Kerry to Barney Frank's Fanny Mae shenanigans. And down the stretch they come!