A lot of people are wondering how health care reform would've gone differently if Hillary Clinton had been president. It's a question that interests people because Democratic primary voters had a choice between her and Obama, and we want to know if we did the right thing.
But there's a slightly different question that's actually more relevant to our choice. How would health care reform have gone if we had nominated Hillary Clinton? And here I think the answer is: significantly worse.
The big question I have about a world where we nominate Hillary is: Does Al Franken still win the Minnesota Senate race? After a long recount, dragged out by Republican legal challenges aimed at keeping Democrats down a Senate seat, Franken prevailed by 312 votes out of nearly 3 million cast. With a margin so thin, the question of who's at the top of the ticket could very well have made the difference.
There's some reason to think that Obama was more appealing to Minnesota voters than Hillary was. (I think Nick made this argument at some point but I can't find it.) Looking back at the primary, Hillary's strength was concentrated in the Appalachians. Obama did better in areas with either a high black population or a large number of college-educated voters, and Minnesota falls squarely into the latter category. If who does better in the primary is a good proxy for who's going to get a bit of extra base turnout, and thus who gives Franken better coattails, it looks like Obama might've put Franken over the top. And then when it came time to get 60 in the Senate, Franken put health care reform over the top.
I don't think there's any similarly close Senate race we lost where Hillary would've tipped the balance in the other direction. In general, coattail effects probably aren't very large. It's just that this race was incredibly tight, so a bunch of small things made the difference. And that's what eventually allowed us to break the filibuster and pass health care reform.