Beck, the Fox News personality, radio host and author, also said that he may have voted for Hillary Clinton over McCain had Clinton been the Democratic nominee in 2008.
"I can't believe I'm saying this, I think I would have much preferred her as president and may have voted for her against John McCain," Beck told Couric.
Prompted to elaborate by the CBS Evening News anchor and managing editor, Beck said he thinks "McCain is this weird progressive like Theodore Roosevelt was."
"I think John McCain would have been worse," he continued, laughing. "How about this? I think John McCain would have been worse for the country than Barack Obama. How's that?"
Watch the clip here, and come to CBSNews.com tomorrow at 7 p.m. ET for the full interview.
Disclosure: Glenn Beck's book "Arguing with Idiots" is published by Simon & Schuster, a division of CBS corporation; also Mr. Beck and Katie Couric are both represented by Hiltzik strategies.