There are only 26 days until the Republican National Convention opens. Sometime between now and then Mitt Romney will name his choice for vice president. The campaign has been extraordinarily tight-lipped, which shows discipline but makes you wonder if Romney is making the decision in virtual isolation.

None of the front-runners is a loser from either a substantive or political standpoint. But some are better than others. And some are “risky” in ways Romney may not appreciate.

Sen. Rob Portman (R-Ohio) is qualified to be president at a moment’s notice. He’s smart, articulate and not “scary” to noon-Republicans. He can help in a key sate. But the real risk with him is the Romney team would then go on defense for a week or more, trying to deny Romney is Bush 43 redux. (Portman served actually in both Bush administrations.) While he was an able budget-cutter for Bush 43, his boss was not. And more to the point, he won’t help make the distinctions between Romney and Bush, which are significant but already being blurred by the Obama attack machine. Does Romney and his team, which has not be adept at beating back adverse media memes, really want to deal with all that?

Likewise, the “safest” candidate according to conventional wisdom, former Gov. Tim Pawlenty, might bring back the dreaded Romneycare vs. Obamacare debate. Moreover, the VP debate becomes a nailbiter with Pawlenty, who showed himself in the primaries to be a weak debater. Again, he’s a fine Republican but the idea that he is a “do no harm” candidate is a misnomer. More to the point, if Romney wants “do no harm,” he might as well nominate an empty brown bag. The point, of course, is to find a vice president who actually helps, even a little, and doesn’t deflate the base.

Certainly no candidate is risk free. But if you are going to try to win, rather than just play not to lose, Rep. Paul Ryan (R-Wis.) would amplify the message, help in the Midwest and fire up the base. Louisiana Gov. Bobby Jindal has many of the same assets.

A final note: The dark horse in this, I sense, is Sen. Kelly Ayotte (R-N.H.). She has national security and executive experience (as attorney general of her state). She is whip smart and already has shown she can win over independent voters. Sure, Sarah Palin made candidates nervous about VP “newcomers” but Ayotte is no Palin so the comparison may actually work to Ayotte’s advantage. (Why, she really does know her stuff!)

In short, “risk” is in the eye of the beholder. It is risky to throw a wet blanket on the base or pick someone with strong ties to an administration you’d rather not associate yourself with. In reality, you minimize risk by choosing the most competent and most credible contender to drive home your message and to help govern. Romney, as someone who made his living at calculated risk-taking, should understand that.