I’ve been a little surprised by the extent to which the Republican presidential race has avoided a debate about “RomneyCare.” I expected to be one of the key issues in the race, and so far, Mitt Romney has barely had to defend his record at all. With about five months to go before GOP voters start weighing in, it’s largely been a non-issue.

But it’s still out there, just below the surface.

In an interview with Laura Ingraham, Sen. John Thune — one of the original conservative elite heartthrobs earlier this year until he opted against a run — said Mitt Romney needs to go further than he has when it comes to the Massachusetts health care plan.

“Would you advise Mitt Romney to say something different today on RomneyCare than he has?” Ingraham asked.

“Well, I think it would be great, I suppose if he would come out and, I mean I think there are a lot of people who over the years who have, since this thing passed in Massachusetts, have looked at it and said gosh I wish he would come out and then disown it or disavow it,” Thune said. “It doesn’t sound like he is going to do that.”

When Ingraham pressed, asking, “Should he?” Thune answered, “Well, frankly, I would like to see that, but I am not advising the campaign.” [emphasis added]

It’s easy to forget, but six months ago, this was one of the key questions in Republican circles: would Romney apologize for his only accomplishment in government? Sen. Jim DeMint (R-S.C.) expected one, but he was hardly alone. Mike Huckabee said Romney should express regret for his health care policy, and so did Rudy Giuliani. Karl Rove urged Romney to admit he was wrong; and prominent conservative activists throughout the GOP base also demanded he “acknowledge he made a mistake.”

Romney, for good or ill, ignored all of this in the Spring, and the calculation appears to have largely paid off — the questions have faded and the race has moved on.

But John Thune is a considered a Golden Boy in many Republican circles, and the fact that even he still wants Romney to “disown” or “disavow” the Massachusetts reform law suggests the issue hasn’t completely gone away.

For the record, in case anyone’s forgotten, Romney’s health care accomplishment is his only success story during his only experience in public office, but it became toxic when it helped serve as the blueprint for the Affordable Care Act. “RomneyCare” even includes an individual mandate, which the Republican mainstream now considers fundamentally evil.

If this somehow becomes a dominant issue in the GOP presidential race, I’m still not sure how Romney prevents this from becoming a huge mess.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.