(AP Photo/Mary Altaffer)

The Romney campaign has floated the idea of choosing a runningmate well ahead of the late August Republican National Convention and speculation on who it might be has reached a fever pitch. It won’t be Condoleeza Rice, Matt Drudge’s credulous reporting notwithstanding. Here are seven possibilities.

Tim Pawlenty

REUTERS/Eric Thayer

The former Minnesota governor has it all, except for charisma. Maybe even that is a plus, since it means he won’t challenge the wooden top of the ticket for the limelight. He’s an evangelical. He’s from the Midwest. He’s reliably conservative and on his few apostasies, such as support for cap-and-trade, he has already abjectly apologized when he was briefly a presidential candidate himself. By quickly endorsing Romney and serving as a loyal surrogate for him, Pawlenty has curried favor in Romney’s camp. After being nearly selected as John McCain’s running mate, Pawlenty may finally get his turn.

Senator Rob Portman (R-OH)

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When it comes to experience, Portman would seem to be the full package. He’s been a congressman, a US trade representative, a director of the Office of Management and Budget and is now a senator. He hails from the crucial swing state of Ohio. The only problem is that he worked in the Bush administration, and who wants to be reminded of that? Romney is emphasizing deficit reduction and Portman presided over some serious deficit spending at OMB. Meanwhile Romney is being hit for his record of offshoring jobs while at Bain Capital, and Portman did nothing to curb that as US trade representative Still, Romney appears to think he can win by running on Bush’s platform, so why not do it with a veteran of Bush’s tenure?

Senator Marco Rubio (R-FL)

REUTERS/Jonathan Ernst

Every conservative in the country loves Rubio, and maybe that’s the problem. Rubio is an immensely talented politician, an inspiring stump speaker who has an Obama-esque ability to turn his life into a patriotic story of America itself. The contrast with Romney could not be starker. Rubio’s parents are immigrants from Cuba, which Rubio loves to discuss. Or he used to. Rubio would claim they fled Castro’s Cuba, although it turns out they left before Castro took power and actually briefly returned afterwards. The Tea Party movement from across the country actively supported his Senate candidacy in 2010. The nationally obscure former Florida State Senate majority leader became a right wing icon. Many conservative leaders and pundits have talked up Rubio as a vice-presidential nominee. Republican candidates in the primaries, such as Romney and Newt Gingrich, praised Rubio and hinted that he’d be on their running mate shortlist. Rubio is Cuban-American, and he has sought to find a middle ground between the xenophobic right and the mainstream on immigration policy. So Republicans hope he would help reduce their deficit among Latinos.

But Latinos are not a monolith: Mexican-Americans in the Southwest won’t necessarily see much in common with a Cuban-American from Florida. Rubio is only 41, so his experience in national politics is very short and his private sector experience is virtually nonexistent. All of that would undermine Romney’s main argument against Obama: that he lacks the experience to revive the economy. And Rubio has an unknown number of ugly skeletons in his closet: his best friend, Representative David Rivera (R-FL), has been under investigation for many potential ethical and legal lapses. ABC News reports, “Featured prominently in the non-partisan Citizens for Responsibility and Ethics in Washington 2011 ‘Most Corrupt’ list, Rivera has been ‘under investigation by at least five different law enforcement agencies for a range of violations,’ including payments he allegedly received in connection with the successful campaign (led, at times, by his mother’s consulting firm) to legalize slot machines at horse and dog-racing tracks.” His brother-in-law, with whom he is also close, was convicted of drug trafficking. And the Florida GOP had numerous corruption issues during Rubio’s rise. There may yet be a lot we don’t know about him. Then there’s the risk that his charisma and popularity among the base would overshadow Romney, as Sarah Palin did John McCain. He would be a high-risk, high-reward pick, like Palin. And we all remember how that turned out.

Governor Bobby Jindal (R-LA)

REUTERS/Lee Celano

Louisiana isn’t a swing state, Jindal is not a Protestant (he’s Catholic) and he didn’t endorse Romney in the primaries: he vociferously backed Texas Governor Rick Perry. And yet his name keeps bubbling back up to the surface. The reason? He was Marco Rubio before Rubio: the smart, young, staunchly conservative great non-white hope (he’s Indian-American). Social conservative leaders say that they like Jindal and his selection would enthuse them. Rachel Maddow jokes that maybe Jindal’s cuts to Medicaid for children in his state will compensate among conservatives for Romneycare in Massachusetts. So Jindal would go over well with the base, while Romney would hope his background would make him more appealing to swing voters than a white man with the same record.

Representative Paul Ryan (R-WI)

REUTERS/Darren Hauck

Ryan offers some of the same costs and benefits as Rubio. His radical right-wing budget proposals have thrilled the Tea Party. He is a hero to them and would increase their enthusiasm for the ticket. Unlike Rubio, he also has gotten the undeserved reputation among the mainstream media as some sort of responsible advocate of deficit reduction. Like Pawlenty, he hails from a slightly Democratic-leaning upper Midwest swing state. He is young and handsome, and he has more experience in national politics than almost any of the other contenders. The problems with Ryan are that his popularity among the Republican base might highlight Romney’s lack of the same, and the unpopularity of his actual ideas. While mainstream pundits praise Ryan for offering a plan to balance the budget over the long term, his way of getting there is to block grant Medicaid and food stamps, privatize Social Security and turn Medicare into a private premium support plan. None of this polls well, especially among Republicans’ single most-important constituency: the elderly. He also would make enormous cuts to all other domestic discretionary spending. Although he refuses to specify what they would be, there would be no way for him to meet those targets without virtually eliminating popular federal programs from Section 8 housing vouchers to support for special education. Democrats could have a field day dissecting those proposals. They could also point out that Ryan’s supposed fiscal responsibility is belied by his votes for every budget-busting initiative under the Bush administration.

Senator John Thune (R-SD)

REUTERS/Jonathan Ernst

Romney is notoriously risk-averse, and Thune would be a very safe choice. He’s good looking in a generically all-American way. He’s middle-aged. He’s an evangelical from the Great Plains. Although he’s reliably conservative he has never made alienating, divisive comments the way, say, Rick Santorum, has. But the career politician undoubtedly hails from the establishment wing of the GOP. The Tea Party might object to his penchant for earmarking and his votes in favor of the bank bailouts. But if they can live with Romney’s much greater apostasies, they will surely reconcile themselves to Thune’s.

Governor Chris Christie (R-NJ)

REUTERS/Rick Wilking

Reports on Wednesday that Christie had been tapped to give the keynote address at the Republican National Convention were apparently premature. If true, that would mean Christie is out of the running for the vice-presidential slot. Christie’s chances are looking slim, in any case. Christie’s greatest asset is also a major liability: his obnoxious, bullying attitude. Tea Party Republicans love it, but swing voters might not. Romney’s aides dished to the New York Times that Christie’s temper concerns them. Picking Christie would also disappoint some social conservatives, who complain that he has been reluctant to oppose gay marriage.

Especially in light of Romney’s many flip-flops, whoever he ultimately picks will have to be a fairly consistent conservative. But merely being a conservative is not good enough: Sarah Palin is conservative, but she was a disaster, and Romney wants to avoid repeating John McCain’s mistake in picking her. Click here to read all of The Nation’s coverage of the 2012 race.