Pro-Santorum super-PAC making big ad buy in Michigan

The Red, White and Blue Fund super-PAC supporting Rick Santorum is launching a major ad buy in Michigan on Thursday.

The fund announced it had made a television and cable ad buy of $663,500 in the Wolverine State. By comparison, the pro-Mitt Romney super-PAC Restore our Future has reportedly spent over $650,000 on anti-Santorum advertising in Michigan. 

"As we’ve seen throughout this election cycle, the Romney campaign is good at two things: spending tons of cash and tearing others down.  It won’t work here," Roy said in a statement Thursday.  "While we won’t get pulled into the type of ‘spitting’ match that Romney likes to engage in, we also won’t let attacks go unanswered."

The ad buy comes the same day Michigan Gov. Rick Snyder (R) backed Romney for president.

Santorum is hoping for a significant victory in Michigan, Romney's native state, which Romney won in the 2008 presidential election over Sen. John McCain (R-Ariz.) by nine points. Santorum's campaign has released a number of ads attacking Romney and stressing Santorum's appeal toward blue-collar workers, which the candidate thinks will play well in industrial Michigan.

A new Detroit News poll released Thursday found Santorum leading Romney in Michigan, 34 percent to 30. The poll also found Newt Gingrich at 12 percent and Ron Paul at 9 percent.

Richard Czuba, the pollster for the survey, said that Romney is "fighting for his political life in this state."

— This story was last updated at 11:54 a.m.