In Georgia, for example, the former president revealed an unusual family rule dating back to his childhood.

“You know, years ago, my dad — I had a great dad, he’s a tough guy — he always said, ‘Never use the word Nazi,'” Trump said. “And he said, ‘Don’t ever use the word Hitler, don’t use that word.'”

“Well, it’s just weird,” Colbert said. “You can’t say ‘Hitler?’ What does this mean? It’s not a bad word.

He revealed his impression of Trump.

“My father said ‘you can’t say Hitler, okay?’ Don’t you dare take his name in vain,’” Colbert said in his Trump voice, then explained what happened when someone said the name in the Trump house.

Find out in his “Late Show” monologue from Tuesday night: