Senate Budget Chairman Kent Conrad (D-N.D.) speaks about fiscal 2013 spending levels at a news conference at the Capitol. (T.J. Kirkpatrick/Getty Images)

But Sen. Kent Conrad (D-N.D.) told reporters that he will not ask senators to vote on the proposal, which would slash deficits by $5.4 trillion over the next decade through spending cuts and higher taxes, acknowledging that the political landscape will most likely not allow members of either party to take the tough votes the plan would require until after the election.

He said the proposal represented a “middle-ground, consensus solution to the country’s fiscal imbalance.”

“I know that taking this route will disappoint some on both sides of the aisle, including some Democrats who would like another plan to rally around and some Republicans who want another plan to attack,” he told reporters. “But I am not interested in furthering the political divide. I am focused on getting a positive result for the American people.”

Conrad, who has announced that he will retire when his term ends, had been widely expected to introduce a budget that would represent a Democratic vision for deficit reduction. He had promised he would move ahead with a committee mark-up, in which members of both parties could offer amendments.

His decision to instead offer a new version of the Simpson-Bowles deficit reduction plan, which has been circulating since it was devised by a presidential commission in December 2010, could be a sign that Democratic leaders have decided that it was politically unwise to require vulnerable members from swing states to vote on a partisan blueprint that would have no chance of adoption.

It gave Republicans a new opening to hit Democrats for failing to advance a budget in the Senate for nearly three years.

Republican Sen. Jeff Sesssions (Ala.), the ranking member of the Budget Committee, said Conrad’s action was a sign that Democratic leaders had decided to pursue a plan to “evade responsibility” and avoid tough votes.

“That’s what you’re in the Senate for. What else are we here for?” he said. “They don’t want to be held accountable for anything.”

But Conrad insisted that his goal is to start a bipartisan conversation about the kind of grand bargain he said will be necessary to deal with deficit reduction, as well as the expiration of the Bush-era tax cuts and automatic spending reductions, both set to take place Jan. 1.

He said those conversations will take time, and introducing the plan now will allow them to unfold in coming months.

“We need to start the discussion and the negotiations now if we’re going to be ready for what we all know is coming next year,” he said.

He and other Democrats say that the deal reached last summer to raise the nation’s debt ceiling took the place of the normal budgeting process, by writing spending caps for the next two years into law.

Proponents of a Simpson-Bowles approach to reducing the debt were deeply disappointed by a vote in the GOP-led House this month on a budget resolution that resembled their plan. Only 38 members of the House — 16 Republicans and 22 Democrats — supported the plan. Conrad said the dismal result was a sign of why more time is needed before a vote is held on the idea.

The plan would reduce deficits from 7.6 percent of the gross domestic product in 2012 to 1.4 percent in 2022.

It would do so by reforming entitlement spending and cutting discretionary spending to historically low levels. Overall spending would fall to 21.9 percent of GDP by 2022.

But deficit reduction would also come through a reform of the tax code that would eliminate loopholes to lower rates. Unlike Republican tax reform proposals — which would call for a new tax system that would produce no new revenue to help pay down the debt — the Simpson-Bowles plan would allow revenue to rise over time. Over the next 10 years, revenue would rise to 20.5 percent of GDP.

Rep. Pete Sessions, R-Texas, said he could not work to negotiate a deficit reduction plan centered on the proposal because it would include tax increases.