“The cost of not releasing the returns are clear,” said conservative columnist George Will, on ABC’s “This Week.” “Therefore, he must have calculated that there are higher costs in releasing them.”

On the ABC roundtable, Republican strategist Matthew Dowd had a similar take.

“There’s obviously something there, because if there was nothing there, he would say, ‘Have at it,’” Dowd said. “So there’s obviously something there that compromises what he said in the past about something.”

“Many of these politicians think, ‘I can do this. I can get away with this. I don’t need to do this, because I’m going to say something and I don’t have to do this,’” Dowd said. “If he had 20 years of ‘great, clean, everything’s fine,’ it’d all be out there, but it’s arrogance.”

In the last week, several Republicans have advised Romney to release his returns. That list includes former Mississippi Gov. Haley Barbour, former RNC chairman Michael Steele and Alabama Gov. Robert Bentley, who called for “total transparency” and said he releases all his tax returns. On “Fox News Sunday,” the Weekly Standard’s editor Bill Kristol added his voice to the list as well, calling for Romney to “release the tax returns tomorrow” and “take the hit for a day or two.”

The speculations from Will and Dowd jibe with what Obama surrogates have been saying, and reveal why the president’s backers see a political benefit to harping on Romney’s tax returns.