Ohio Gov. John Kasich warned on Sunday that the next commander-in-chief must not tolerate Russian aggression, sending a clear message to Donald Trump who has periodically commended Russian Prime Minister Vladimir Putin for his “strong” leadership.

“Putin, I think, is a thug. He wants to reconstitute the old Soviet Union and it’s not going to happen,” Kasich told CNN in a pre-taped interview. “The West needs to make it clear to Putin that we don’t tolerate this behavior.”