From left, Erskine Bowles, Senator Alan Simpson, Dr. Alice Rivlin and Senator Pete Domenici on Capitol Hill in 2011. (Melina Mara/The Washington Post)

Erskine Bowles and Alan K. Simpson, the deficit-cutting duo who have been trying for three years to broker a budget deal, are back in Washington with a new message for the nation’s policymakers:

You’ve done the easy stuff. You’ve done the stupid stuff. Now it’s time to get serious.

With another fight over the federal debt limit looming later this year as perhaps the final crucible for forging bipartisan consensus, the former chairmen of the famed Bowles-Simpson debt-reduction commission began briefing lawmakers Thursday on their latest plan for getting the nation’s runaway debt under control.

In a major concession to political reality, Bowles-Simpson 2.0 seeks far less in new taxes than the original, and it seeks far more in savings from federal health programs for the elderly.

But it would end the sequester, the sharp, across-the-board cuts to agency budgets that took effect March 1. And it would eliminate the legal cap on government borrowing, proposing a new system that would let the U.S. Treasury keep borrowing as long as the debt does not grow as a percentage of the nation’s economy.

The battle over the 2014 budget

All told, the plan urges policymakers to enact $2.5 trillion in new taxes and savings over the next decade, significantly more than the $1.8 trillion plan President Obama has put on the table. In a report set for public release Friday, the pair argue that Obama has set his sights too low and that more must be done to push down a debt that is now higher, as a percentage of the economy, than at any time in U.S. history except for the end of World War II.

“I think this is our last chance. I don’t think there’s any chance after the end of the fiscal year because we’ll be back into politics again,” Bowles said in an interview. “We’ve done the easy stuff: We put a cap on discretionary spending and we raised taxes on rich people. What else are we going to do?”

Coming after years of bickering over the budget — and one day after the U.S. Senate couldn’t agree on changes to the nation’s gun laws — the new Bowles-Simpson plan evoked a weary shrug on Capitol Hill. Some Democrats criticized the proposal, saying the decision to cede ground to Republicans on both taxes and health spending could damage the pair’s credibility.

“In some ways, this threatens to erode the Bowles-Simpson brand,” said Rep. Chris Van Hollen (Md.), the senior Democrat on the House Budget Committee. “The original commission report has been a useful yardstick for measuring other proposals. But to the extent they keep changing the yardstick, it makes it more difficult for people to compare proposals.”

Other lawmakers welcomed the plan, saying it could help advance Obama’s outreach to Senate Republicans and break the partisan stalemate over taxes and entitlement spending.

“The more new ideas that are put out there, the better chance we got,” said Sen. Saxby Cham­bliss (R-Ga.), a leader in the campaign for a bipartisan debt-reduction deal.

In addition to the proposal to get rid of the dollar-based debt cap, the new Bowles-Simpson plan offers a number of innovations compared with the recommendations adopted by a majority of fiscal commission members shortly after the 2010 election. There’s a novel approach to raising the Medicare eligibility age to 67 from 65 that would permit people to buy into Medicare before their eligibililty date. And there are numerous new ideas for protecting the poor from tax hikes and program cuts.

Also Thursday, the Bipartisan Policy Center issued a report on health care that aims to move the debate away from House Budget Committee Chairman Paul Ryan’s contentious proposal to replace the open-ended Medicare guarantee with federal “premium support” payments to purchase private insurance.

The center’s leaders — former senators Tom Daschle (D), Bill Frist (R) and Pete V. Domenici (R), as well former Clinton budget director Alice Rivlin, who has in the past advocated premium support — now call for a series of Medicare reforms aimed at driving the cost of health care down across the board, in part through increased competition among providers.

If successful, the group said, the reforms would reduce Medicare spending by $435 billion over the next decade and make the per capita spending caps sought by Ryan (R-Wis.) unnecessary.

The new Bowles-Simpson plan calls for even more health savings — $585 billion over the next decade — to be paired with $585 billion in higher taxes through an overhaul of the tax code. The plan would also switch all government programs over to the chained consumer price index. And it calls for an additional $700 billion in other spending cuts and “program integrity” initiatives.

Together with previous debt-reduction deals and savings on interest payments, the Bowles-Simpson plan would bring total deficit reduction to $5.2 trillion over the next decade, Bowles said — roughly $1.3 trillion less than the original Bowles-Simpson plan, but enough to push the debt below 70 percent of GDP by 2023 and put it on a downward path in future years.

“While the deficit reduction enacted to date since FY 2011, totaling nearly $2.7 trillion over ten years by some measures, represents notable progress,” the report says, “our debt problems remain far from solved.”