On election night, Mr. Clinton grew playfully competitive with his wife over who had done more events or had had more impact, Mr. Rendell said. Mrs. Clinton was superstitious and rarely watched election night coverage, but in the hotel suite, Mr. Rendell showed her husband county-by-county returns.

“The president wanted to know exactly what the returns were in the places he had been and Hillary hadn’t been,” Mr. Rendell said. “He kept showing Hillary, and she would laugh.”