"I think she'd be very tough to beat now," Clooney told E! News.
"And you know, all of the things that people thought of her as polarizing in 2008, don't exist at all [anymore]," he said. "I think there's one last glass ceiling to be broken and I think she could do a great job with it."
Asked if the former first lady and secretary of state could count on Clooney's vote if she runs, the actor smiled and said, "Of course!"