I did not think that Mitt Romney would choose the Wisconsin congressman Paul Ryan as his running mate. Nor did I think that Romney should pick Ryan as his number two. But now that he’s done so, let’s consider what might have made the presumptive Republican nominee choose the way he did.

1) Ryan is a formidable political talent. Three years ago, the congressman was well- known only to his conservative admirers, and his plans for reforming entitlements were so radioactive that only Democrats wanted to talk about them. Today, the Ryan budget is the congressional G.O.P.’s governing agenda, and Ryan himself is a darling of the Beltway media. What’s more, he’s accomplished all of this while representing, not a safe-as-houses Republican seat, but a blue-collar district that went for Barack Obama by four points in 2008. He’s not a brilliant orator, but he has some of John McCain’s skill at selling himself in town halls and some of Ross Perot’s flair for data presentations, and his persona is exactly right for the message that he’s pushing: Wonky, earnest, non-threatening, all-American. (Plus: Cute kids!) He obviously has never experienced anything like the glare of the presidential campaign trail, but he has more experience in the spotlight than most of the other alternatives available to Romney — and if part of the case against a figure like Pawlenty was that he had seemed to wilt in the primary-season heat, then the fact that Ryan has thrived as the de facto leader of the opposition these last two years, despite unrelenting Democratic attacks, has to count as a strong point in his favor. There’s something to be said for just picking the best available politician in these circumstances, and even Ryan’s fiercest critics acknowledge that he’s pretty good at the business of selling himself and his ideas.

2) Ryan will help Romney govern. If the Republican ticket triumphs in November, having Ryan on-side will help Romney, a non-Washingtonian, navigate the complexities of Capitol Hill. But here it’s important to keep in mind that Ryan is an ideologue and a Beltway wheeler-dealer, attuned to both the possibilities for bipartisanship (recall that his latest Medicare proposal is co-sponsored with a Senate Democrat) and the need to sometimes swallow hard and take one for the team (hence those Bush-era votes for TARP and Medicare Part D). Thus if Romney wants to push an aggressive agenda in his first hundred days or year in office, Ryan will be a natural point person — but if the Romney White House then needs to compromise well short of conservative objectives, Ryan will be capable of negotiating the deal and ready and willing to sell it to a reluctant base. What’s more, having Ryan as a loyal administration foot soldier (whose own presidential ambitions are bound up in Romney’s success) will prevent the Wisconsin congressman from setting up a rival center of power within the party, or becoming a locus of conservative dissent. Some conservatives may think that the Ryan choice brought Romney permanently on-side for their ambitions. But it’s also possible that the choice will ultimately be remembered as the moment when Romney co-opted conservatives instead.

3) Ryan fits the demographic profile Romney was looking for. This is an election that will be won or lost for Republicans among swing voters, many of them Catholic, in the Midwest and Old Northwest. Ryan is a Catholic politician from Wisconsin, a state that the Romney campaign has some hope of tipping into its column in November, and there’s at least some polling evidence that a Romney-Ryan ticket would overperform in the Badger State. He brings some of what Pawlenty and Rob Portman offered, in this sense: He has long experience campaigning and winning among the kind of voters Romney desperately needs to win. And it doesn’t hurt that he’s also a youthful-looking family man who makes a nice visual complement to Romney on the stump. (Just watching them together this morning, there’s a potential father-son, older partner-junior partner dynamic there that might be helpful to a candidate heretofore somewhat lacking in the human touch.)

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None of these three points, however, change my basic skepticism about the pick. This is a game-changer, of a sort: Romney has been running a cautious, content-free campaign, and picking Ryan will effectively force him to become much more substantive on policy, while giving the country the clearest possible choice heading into November. But setting up a clash of worldviews doesn’t address Romney’s most glaring policy weakness, which is the (understandable) fear among hard-strapped voters that Republican policies will benefit the rich more than the middle class. Ryan’s association with entitlement reform is at best orthogonal to that weakness, and at worst it exacerbates it substantially. What’s more, by picking him Romney may have passed up a golden opportunity to take advantage of the Obama campaign’s leftward tack over the last year: Instead of making a sustained play for the center of the country, he’s chosen to raise the ideological stakes.

This will make the race more exciting and more serious, and I’m looking forward to watching it play out. But I don’t think it’s made a Romney victory more likely.