A word of caution to future guests on The Diane Rehm Show: Don’t be late.

Former Maryland Gov. Martin O’Malley, a 2016 presidential candidate, learned that the hard way during an interview Tuesday morning on the show, produced at WAMU in Washington, D.C.

“Governor O’Malley, I must say, I’m somewhat surprised that you could not make it here in time as you had promised to,” Rehm said at the beginning of the segment.

“Well Diane, you can’t believe every promise every politician makes,” said O’Malley, who was calling in by phone. “I sincerely apologize. I am on Military Road right now, and we are following all of the applicable rules of the road, but we do not control the traffic accidents. I should have left even earlier.”

“Yeah, absolutely,” Rehm said. “I am disappointed because, as you well know, it’s a national interview on NPR, and I do expect guests to live up to their promises.” Rehm then moved into discussing O’Malley’s long-shot presidential run, and the shamed governor did eventually arrive at the studio.

Here’s the full segment:

[via The Hill]