The heated debate over the federal deficit has pumped new life into controversial proposals for requiring Americans on Medicare to pay more for their healthcare, raising the possibility that seniors' medical bills could jump hundreds or even thousands of dollars. It remains unclear if any of the proposals, which congressional Republicans have demanded to cut trillions of dollars from the federal budget, will be enacted this year, given the continued stalemate over government spending. But the ideas, once considered politically toxic, have gained enough traction that many in Washington expect them to resurface, if not now, then after the 2012 election. "Over the long haul, beneficiaries will have to pay more and taxpayers will have to pay more," said Henry Aaron, a longtime healthcare expert at the Brookings Institution. "It's just too darn expensive."