“Very unlikely. Too much water under the bridge,” Mr. Kasich said in an interview with CNN this week.

Mr. Kasich, a former 2016 GOP presidential candidate himself, said it’s still important to get out the vote for people like Sen. Rob Portman, who is running for re-election in Ohio.

“We want to get people out to vote. We want to re-elect Senator Portman, and we want to re-elect people down ticket,” Mr. Kasich said.

“I’m not voting for Hillary,” he said.