Clinton-Obama, Obama-Clinton

Why should Sen. Obama promise to make Sen. Clinton his running mate and to share the presidency with her? Because half a loaf is better than none, and without this deal he may end up with nothing—neither the presidency nor the vice presidency nor a great shot at becoming president later in life.

This last point is worth stressing. If Clinton were to win the nomination and choose someone else as her running mate, what would happen to Obama? Were Clinton to lose to John McCain in the general election, Obama could of course run again in 2012. But among Democrats in the modern era, the only candidates besides incumbent presidents to have actually won the presidency were fresh faces—that is, candidates running for the presidency for the first time. Democrats love fresh faces—JFK in 1960, Jimmy Carter in 1976, Bill Clinton in 1992. Prominent non-incumbent Democrats on their second or third tries for the presidency have either failed to get the nomination—like Hubert Humphrey in 1972, Jerry Brown in 1992, and John Edwards this year—or lost in the general election, like Adlai Stevenson in 1956, Humphrey in 1968, and Al Gore in 2000. Presidential competition within the Democratic Party is thus especially fierce because each candidate realizes that, most likely, it is now or never. (Competition among Republicans, by contrast, is generally tamer because the GOP loves political encores and is better at electing decidedly unfresh faces. Several Republicans have won the top prize on their second or third try—Richard Nixon, Ronald Reagan, and the first George Bush, for example. McCain hopes to join their ranks this year.)

Alternatively, if Clinton heads up an Obama-less ticket this year and beats McCain, Obama's chances of making it to the presidency would become even worse. Challenging a Democratic incumbent in 2012 would be an uphill battle, so Obama would probably need to wait at least until 2016, at which point he could very well face stiff party competition from whomever Clinton picks as her running mate. The fact that Obama's presidential prospects would be worse if Clinton were to win on her own than if she were to lose to McCain highlights another tactical truth: Even if Clinton has the votes at the convention to prevail and the power to pick someone other than Obama as her running mate, it might be unwise to do so, given that Obama might have diminished incentives to deliver his ground troops for her come November.

Of course, everything in this analysis is symmetrical: We could switch the names Obama and Clinton in the preceding paragraphs and the points would be equally valid. A half-loaf for Clinton is better than none; and if Obama ends up on top of a Clinton-less ticket, she loses her own best chance ever to become president. Most important, were Obama to run without Clinton, she might actually be better off if he were to lose the general election to McCain; and this, in turn, gives him a good tactical reason to put her on the ticket, so that she and her most ardent supporters have the proper incentives.