Ryan, a budget-cutting Republican who sought to privatize Medicare, and Wyden, a Democratic advocate for the elderly, say their plan avoids "heated partisan rhetoric" to provide the best options for seniors.
The White House, however, reacted negatively.
"We are concerned that Wyden-Ryan, the proposal you mentioned, like Congressman Ryan's earlier proposal, would undermine rather than strengthen Medicare," White House spokesman Jay Carney said. "The Wyden-Ryan proposal could, over time, cause the traditional Medicare program to 'wither on the vine,' because it would raise premiums, forcing many seniors to leave traditional Medicare and join private plans. And it would shift costs from the government to seniors.
"At the end of the day, this plan would end Medicare as we know it for millions of seniors. The Wyden-Ryan proposal is the wrong way to reform Medicare. That's our position."
The plan, released Thursday at a breakfast sponsored by the Bipartisan Policy Center, would keep the 46-year-old, government-run Medicare program as an option for new retirees starting in 2022, along with a variety of private plans.
"Before the partisan attacks begin to escalate and the 2012 election ads start to air, we are outlining a plan for how Democrats and Republicans can work together to ensure that American retirees -- now and forever -- have quality, affordable health insurance," the lawmakers write in their report, "Guaranteed Choices to Strengthen Medicare and Health Security for All: Bipartisan Options for the Future."
"Our plan would strengthen traditional Medicare by permanently maintaining it as a guaranteed and viable option for all of our nation's retirees. At the same time, our plan would expand choice for seniors by allowing the private sector to compete with Medicare in an effort to offer seniors better-quality and more-affordable healthcare choices," the report states.
Senior citizens and others receiving Medicare would still get a predetermined amount of government money to buy insurance, as they would under the Medicare proposal Ryan included in the budget blueprint that passed the House last year, they said.
But the new approach would let that subsidy, known as premium support, rise or fall along with the actual cost of the policies -- protecting seniors from added expenses, The Washington Post reported.
Ryan and Wyden told the Post their plan might not save Washington any more money than under the current law.
But they said forcing private insurers to bid to provide Medicare coverage, and encouraging beneficiaries to choose the least expensive plan, could drive costs down more than the current law's private-sector price controls.
Ryan said he expected no action to be taken on their proposal until the 113th Congress is seated in 2013.
Still, "we want to demonstrate that there is an emerging consensus developing on how to preserve Medicare. We want to move that consensus forward," he told the Post. "This program's got to be reformed to be saved. The country's at stake."
Blending traditional Medicare into Ryan's premium-support plan "places traditional Medicare, long supported by progressives, alongside a menu of private alternatives that provide the choice and competition long supported by conservatives," in effect combining the best ideas of both parties, Wyden told The New York Times.
Wyden told the Post the proposal would "address the real challenges" of the federal entitlement program -- rising health costs and an aging population.