Ron Brownstein, fresh off pondering Obama and McCain's potential for bipartisan governance in the latest Atlantic, explains why bipartisan tickets are a bad idea:

... only two presidents have actually taken the leap of choosing a vice president who was not firmly attached to their party. And their experiences suggest that in practice, a fusion ticket is the wrong means to a worthwhile end.

For starters, Obama or McCain would probably see their life insurance premiums soar if they made such a selection. The two previous presidents who choose running mates not clearly identified with their party both died within weeks of taking the oath of office. The aged William Henry Harrison, a Whig elected in 1840, died of pneumonia one month into his term; Abraham Lincoln was assassinated six weeks after his second inauguration in 1865.

Each man's death elevated to the presidency a vice president not solidly committed to the program of the deceased president's party. Over time it turned out that the new president was, in fact, closer to the opposition party in which his roots were planted. Perhaps this should not have been a shock, but in each case it provoked a political civil war.

Brownstein goes on to recount the cautionary tales of John Tyler and Andrew Johnson, whose presidencies foundered amid vicious conflict with the party they technically represented, but didn't really belong to. God willing, a Vice President Lieberman wouldn't end up thrust into the Presidency, but the fates of the Tyler and Johnson Administrations do make for cautionary tales as McCain ponders his choice.

I would add, though, that Brownstein's analysis offers a reasonable case for a pro-lifer to actually feel at least slightly better about a McCain-Lieberman ticket than about, say, a McCain-Ridge (or McCain-Rudy!) pairing. Lieberman's record on domestic issues and partisan affiliation more or less guarantee that he would only succeed McCain if McCain died in office, and the examples of Tyler and Johnson, as well as common sense, suggest that in that eventuality he wouldn't be embraced as the GOP's standard bearer for 2012. As veep, his most likely role would be as a Cheney-style partner in power, with a strong foreign policy portfolio and no plausible post-Administration ambitions of his own. By picking Ridge and Rudy, by contrast, McCain would be selecting a semi-plausible successor figure, and one with the capacity, however small, to move the GOP in a pro-choice direction in a way that a Vice President Lieberman almost certainly couldn't. Not that McLieberman isn't still a bad idea, mind you - but from a pro-life perspective, McRidge and McRudy seem a whole lot worse.

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