Obama for America campaign manager Jim Messina told potential donors that Mitt Romney made ‘a strategic pick that carries real danger for us’ in choosing Paul Ryan as his running mate.

“You might be wondering why the hell Romney picked this guy. But this is a strategic pick that carries real danger for us,” Messina wrote tonight. “Here’s the calculation: Mitt Romney doesn’t need or expect Paul Ryan to convince even one undecided voter to cast their ballot for him . . . He’s there to reassure and inspire ultraconservative ideologues and corporate interests that they will have one of their own a heartbeat from the presidency.”

Messina explained that Ryan would generate fundraising buzz for Romney that would generate “TV ads — lying, distorting and trashing Barack Obama. Those ads will have more impact on undecided voters than anything Paul Ryan himself does or says.”

Public Policy Polling, a Democratic-leaning pollster, found that Ryan has a strong approval rating among senior citizens in Ohio (38 percent approve of Ryan, while 29 percent disapprove). “Ryan’s favorability numbers in Ohio are actually *best* with seniors at 38/29,” PPP tweeted in a teaser for poll results that they’ll release tomorrow.

If that number holds, Messina has a bigger problem than he’s ready to admit.

Here’s the full message from Messina:

Congressman Paul Ryan is the poster boy for the extreme Republican leadership in a Congress whose overall approval rating is 12 percent. His plan to dismantle Medicare is deeply unpopular with the general public, and especially undecided voters. You might be wondering why the hell Romney picked this guy. But this is a strategic pick that carries real danger for us. Here’s the calculation: Mitt Romney doesn’t need or expect Paul Ryan to convince even one undecided voter to cast their ballot for him. That’s not what he’s on the ticket for. He’s there to reassure and inspire ultraconservative ideologues and corporate interests that they will have one of their own a heartbeat from the presidency. That means tens or even hundreds of millions more dollars for the Romney campaign and the array of outside groups supporting him — and if current trends hold, more than 90 percent of that money will be spent on TV ads — lying, distorting and trashing Barack Obama. Those ads will have more impact on undecided voters than anything Paul Ryan himself does or says. Mitt Romney is convinced that picking Paul Ryan is a great investment for him. And his campaign is already touting the pledges and donations they’ve received as a result, with fundraising events planned for this week. We’re already being outraised, and we can’t afford to fall further behind. Our records show that you’re still waiting to make your first online donation — now is the time.