He said he thought Hillary Clinton would kick the Republican's "****ing asses" if she decided to run for president in 2016.
He told Playboy magazine: "[Obama's] still a safe dude. But with those Republicans, we're now in a situation where even if he said, 'I want to give you mother****ers a raise', they'd go, '**** you! We don't want a raise!"'
The 64-year-old actor, who has been involved in United States politics since the civil rights movement, added that he was disillusioned with petitions for change on Facebook and Twitter.
He said: "You need to have your physical body out there in the streets and let these people - and the rest of the world - know.
"When our anti-war movement led the world, it was because people could see us in the streets, see our faces, hear the protest music.
"You can't do that **** blogging in a room."
- Independent