Unless the government acts to raise the debt ceiling by Aug. 2, the U.S. will be in default. Ryan, echoing House Majority Leader John Boehner, argued any deficit-reduction plan should include no tax increases and cutting spending by a dollar for every dollar the debt ceiling is raised.

Ryan doesn't expect Congress to reach an agreement by the deadline.

"Look, I don't think we're going to solve 40 years of ideological differences between the two parties by August," he said.

"I think what we ought to do is get a real downpayment, a serious downpayment to the tune of trillions of dollars in spending cuts and savings, with enforcement mechanisms that bank those savings going in so we can buy ourselves some time and space in the credit markets."

Ryan, who announced later Tuesday he will not run for the retiring Herb Kohl's Senate seat, said that if there's "an issue that is unresolved between the two parties — health care, for example — we're going to have to go to the electorate and let them choose in 2012."