DES MOINES — Partway through his stump speech at the Iowa State Fair in August, Representative John Delaney spotted a familiar face walking by.

“Mr. Speaker!” he called from his perch atop The Des Moines Register’s soapbox . “What a nice surprise. Speaker Boehner is in the house. You’re looking good, Mr. Speaker. I appreciate you coming out and supporting me, I really do.”

John Boehner, the former House speaker, wearing a blue-and-white gingham shirt almost identical to Mr. Delaney’s — and looking distinctly as though he wished he had taken a different route from the pork chop stand to the parking lot — was instantly surrounded by reporters.

“I worked on a lot of stuff with him. He’s a good member,” was about all Mr. Boehner, a Republican, would say of Mr. Delaney, a Maryland Democrat running for president. “Oh God. I’m just walking by. If it weren’t Delaney there — I’m walking by, I got a pork chop, I was walking by, I saw Delaney. I said, ‘Aw, I’ll stop.’ I should have known better. I should have kept walking.”