Republicans still aren't budging on Obama's demands for higher tax rates on upper bracket earners, despite the president's convincing election victory and opinion polls showing support for the idea.

Democrats in turn are now resisting steps, such as raising the eligibility age for Medicare, that they were willing to consider just a year and a half ago, when Obama's chief Republican adversary, House Speaker John Boehner, was in a better tactical position.

With less than three weeks before the government could careen off a "fiscal cliff" of automatic tax hikes and sweeping spending cuts, Boehner, R-Ohio, said "serious differences" remain between him and Obama after an exchange of offers and a pair of conversations this week.