REUTERS/Carlos Barria
The Ohio governor told Cleveland.com and The Columbus Dispatch that it's going to be "really hard" for him to back Donald Trump, the presumptive Republican nominee.
"Unless I see a fundamental change it's really hard for me to do a merger," Kasich said in his first interview with his home state's media since ending his failed presidential campaign earlier this month. "If the values are not somewhat similar - if the culture is not somewhat similar - it's hard to do a merger."
"If he changes, that's a whole new ballgame," he continued.
Kasich is one of a handful of Republican governors who has yet to throw his support behind the presumptive GOP nominee.
He said that he, his wife, and his teen daughters have been put off by the Manhattan billionaire's "negativity," but he added that he would not vote for Democratic frontrunner Hillary Clinton.
"That's not going to happen," he said.
Kasich also discussed a book he's working on about his unsuccessful presidential bid.
"How can I let an experience like this not be written about?" he said.
Last week, the Ohio governor shot down the prospects of a third-party bid, which came about after a Washington Post story reported that GOP operatives unhappy with Trump's presumptive nomination were looking for a candidate to run as an independent.
The Post reported that 2012 GOP nominee Mitt Romney made an effort to court Kasich for the bid.
"I'm not going do that," Kasich said. "I gave it my best where I am. I just think running third party doesn't feel right. I think it's not constructive."