Sen. Pat RobertsCharles (Pat) Patrick RobertsOvernight Finance: Lawmakers, Treasury look to close tax law loopholes | Trump says he backs gas tax hike | Markets rise despite higher inflation | Fannie Mae asks for .7B Senators working on fix to agriculture provision in GOP tax law Trump budget would slash crop insurance funds for farmers MORE (R-Kan.) is again facing residency questions from his primary opponent after he misspoke in an interview, saying he returns home to Kansas “every time I get an opponent.”

In an interview with KCMO radio, Roberts was asked about reports that he no longer lives in his home in Kansas and instead rents a room from donors when he returns to the state. That and further reports outlining his relatively infrequent visits home have dogged him in his primary contest with radiologist Milton Wolf and provided fodder for Wolf to hammer him as out-of-touch with his state.

Roberts said his performance shouldn’t be measured on where he lives.

“I don’t measure my competency or my record or the results – and I do get results – on where I put my head on a pillow,” he said.

But pressed on the residency issue, Roberts backed himself into a gaffe.

“Every time I get an opponent – I mean, every time I get a chance, I’m home. I don’t measure my, what, my record with regards as a senator as how many times I sleep wherever it is,” he said.

Wolf immediately seized on the comment, calling it a “slap in the face to Kansans.”

“Kansans understand now more than ever that Pat Roberts doesn’t live in Kansas and he hasn’t for a very long time,” he said.

Residency questions similar to those Roberts is facing have dogged incumbent senators in the past, and most recently contributed to the defeat of former Sen. Dick Lugar (R-Ind.) in his 2012 primary. 

Still, about a month out from the Kansas primary, Roberts looks well-poised for reelection. Wolf has failed to pick up much traction and has suffered from reports about graphic Facebook posts he made in which he provided off-color commentary on his patients’ X-rays.