Via the Detroit Free Press:
Some Michiganders — this reporter included — got what may have been a surprising call over the weekend: Romney’s chief rival Rick Santorum endorsing Mitt Romney.That's so pathetic, I'll bet even Obama cringed when he heard about it. It also shows how desperate Romney's campaign is to win Michigan. If he loses there, he's toast. It'd be nice to see this despicable attempt to save his candidacy actually sink it.
The endorsement was in 2008, when Romney was running for president (and Santorum wasn’t). In an interview about the endorsement at the time, Santorum said he hesitated about who to endorse but decided on Romney as the best alternative to John McCain. The robocall was presumably paid for by either the campaign or the Super PAC supporting Romney.
After a short introduction in the automated call to Michigan voters, Santorum says: “If you’re a conservative, there really is only one place to go right now. I would even argue farther than that. If you’re a Republican, if you’re a Republican in the broadest sense, there is only one place to go right now, and that’s Mitt Romney.”
Here's the audio from the 2008 interview:
h/t Free Republic