Ex-Defense Secretary Donald Rumsfeld says President Barack Obama should either oust Syrian President Bashar Assad or not bother getting involved in the civil-war torn Middle Eastern nation.

Rumsfeld spoke Tuesday afternoon in response to a question during a speech at the Gerald R. Ford Presidential Museum in Grand Rapids. The 81-year-old served as defense secretary under Ford and President George W. Bush.

Rumsfeld says if the U.S. defers action until the United Nations gives the green light, it means the nation ``won't do anything'' unless Russian President Vladimir Putin agrees. He says it's "silly'' to claim that the president need Congress's approval to use military force.

Earlier, Rumsfeld said Obama lost a lot of credibility through indecisiveness in responding to last year's killing of America's Libyan ambassador.