Why would anyone want to be vice president, anyway?

There’s really only one good answer to that: It’s the single best step you can take to the presidency.

Ezra Klein has been pointing out on Twitter that Rep. Paul Ryan probably has more influence over policy, or at least the Republican policy agenda, as chair of the House Budget Committee than he would as vice president. That’s certainly correct.

But if Ryan wants to be president, winning at Veepstakes is the way to go.

It’s difficult to prove much statistically because there are so few presidential nominations and even fewer if we don’t look beyond nomination reform before the 1972 cycle. But just a quick look at the list of presidents reveals lots of former vice-presidential nominees (in the 20th century, both Roosevelts, Coolidge, Truman, Johnson, Nixon, George H.W. Bush), with a few others who became losing presidential nominees (Humphrey, Mondale, Dole, Gore). Now, of course, there are plenty of nominees who were not former running mates, but think about the ratios here: By my count that’s 11 nominees who were once running mates compared with 27 who were not (from 1900 on, counting each nominee only once no matter how many times they were nominated). If you think ratios here, that’s 11 out of a very small number of former vice-presidential candidates, compared with 27 out of a large number of senators, governors, generals who conquered Europe, and other sources of presidential nominees.

Moreover, Ryan isn’t a senator, a governor or a general who conquered Europe. He’s a member of the House, and in the modern era of presidential nominations the closest any of them ever came to a nomination were Dick Gephardt in 1988 and Mo Udall in 1976. In other words, not very close. Perhaps Ryan is different, but the odds would seem to be against it. Could Ryan move up to the Senate or become governor of Wisconsin? It’s possible, but those are much riskier ways to get close to the White House than a VP run.

Among other things, Ryan not being the nominee means that someone else would be, and (as we saw in 2008) there are a lot of structural reasons to expect that any running mate will rapidly develop enthusiastic support of conservatives, especially in a year when the top of the ticket doesn’t inspire that. If Romney wins, that running mate becomes the overwhelming favorite for the next open nomination if he or she wants it. Even if Romney loses, his running mate could be formidable in 2016. And Ryan? Who knows if he would retain his conservative buzz going forward. He would hardly be the first politician to have once been the Best Conservative Hope only to later be found out as traitor to the cause.

Granted, there are all sorts of ways to imagine things going wrong, either in the campaign or later, for a running mate. But that’s true of any future path. And at least as a current or former running mate Ryan would avoid the real toughest thing to overcome in reaching the White House: obscurity.

No, if Paul Ryan wants to be president, then he should want the vice-presidential nomination right now. And that’s true for pretty much anyone; it’s the single best step there is to a future shot at the presidency.