Romney: Santorum's robocalls to Michigan Democrats are "a new low"

“I wasn’t too concerned about what the Democrats are putting out there because I figured it wouldn’t have much impact. But Senator Santorum did something today which I think is deceptive and a dirty trick. He’s put an ad out there sounding like a labor ad telling labor folks to vote against me and vote for Rick Santorum and at the end there’s a trailer that he paid for it but it’s confusing people. It’s a new low in this campaign,” Mitt Romney said on FOX News’ “Hannity” show.