“Probably the biggest differences in the race in Maine may revolve around Senator Santorum and myself,” said Mitt Romney in an interview yesterday on Portland radio station, according to the transcript provided by his campaign. “He’s a strong defender of earmarks. I oppose earmarks. I want to absolutely end earmarks.”

That’s just one example of the many attacks on Santorum’s earmark record that Romney and his campaign have leveled in recent days. Looking to find a way to curtail Santorum’s traction, the campaign seems to have made “earmarks” for Santorum what “Freddie Mac” was for Newt Gingrich.

The Washington Post’s Jen Rubin talked to Santorum today about the charges:

Is he concerned that Mitt Romney’s barrage, most recently about earmarks, will knock Santorum off message? He laughs. “I’ll talk about it. Earmarks are an infinitesimal part of the budget.” He pointed out that in conjunction with the Salt Lake City Olympic games that Romney came to D.C. to seek $300 million in federal earmarks for the games. Santorum added, “You don’t see him go after me for increasing any appropriations account. I stood on the floor of the Senate with a spend-o-meter.” He says, “We have a great plan to cut $5 trillion. . . . and get to a balanced budget.”

Was Romney responsible for that much in earmarks? In The Real Romney, former Utah senator Bob Bennett is quoted as saying, “Most of the federal money was already in place before Mitt came on.” But a 2007 New York Times story paints a different account of what occurred:

[T]he federal government’s contributions, thanks to Mr. Romney, were also immense. By the time the Games were over, about $342 million in federal money to plan and stage the Winter Games had flowed into Utah, a record outlay for the Olympics and nearly $50 million more in constant dollars than was spent for the Atlanta Olympics, according to a report in 2001 by the Government Accountability Office.

And much of that money was from earmarks, which Mr. Romney now often calls politically motivated and wasteful. “These earmarks are embarrassing, and they’re embarrassing for my party as well as the other party,” he said in Marshalltown, Iowa, during a recent campaign swing.

But in the three years leading up to the Games, taxpayers ended up paying for a lot of things that had little to do with downhill racing or the perfect triple Lutz, including $33,000 for an Olympic horse adoption program and $55,000 for the Department of Justice to assess and resolve racial tension in Salt Lake City. More than half of the federal money was spent on security, but the federal government also footed the bill for shuttle buses, drug testing, park-and-ride lots and upgrades to the lighting at Salt Lake City International Airport.

Mr. Romney did reject some spending requests, annoying local politicians. But he also got behind some huge projects that he admitted at the time and in his book were not “must haves” for the Olympics, especially a light-rail system in Salt Lake City that some politicians were keen on having.