I’m sure Joe understands.

(Politico 44) — President Obama said he couldn’t say what impact it would have on the 2012 race if Mitt Romney chose Ohio Senator Rob Portman as his running mate.

“It’s hard to say, I mean, traditionally, the pundits at least, say that the top of the ticket is what matters,” he said in an interview with WEWS broadcast in Ohio Tuesday. “When I chose Joe Biden it was because I was confident he could be president.

“And I think that any nominee should be thinking about not so much the politics of it, but thinking about, could the person you’re selecting carry out their constitutional duties if heaven forbid something happened  to the president.”