"What are the things that I should I forget about your father so that I can keep the image in my head the way I want?" Colbert asked Ron Reagan, son of the 40th U.S. President Ronald Reagan, last night on his show.

"Probably, raising taxes, amnesty for illegal immigrants and, well, one of the most liberal abortion laws in California when he was governor," Reagan said.

The younger Reagan recently published "My Father at 100," a book about his late father's life. He is also an avid liberal, whereas his father was a champion of conservative politics. Recently, Reagan has faced opposition from remarks concerning his father's struggle with Alzheimer's.

"Did you see anything when he was president then said to yourself, 'Huh, that now in retrospect, might be some sign of it'," Colbert asked Reagan.

"Yeah, every once in a while," Reagan said. "As I've said, it'd be like you're watching TV and the focus softens a little and then sharpens back up and you think, huh, I wonder what that was."