WASHINGTON — Congressional leaders are throwing their collective weight behind a hard-won, two-year bipartisan budget plan aimed at heading off a looming government debt crisis and forestalling a government shutdown in December.

The pact, which would take these volatile issues off the table until after the 2016 presidential election, emerged in behind-the-scenes negotiations late Monday on Capitol Hill. It-would give both the Pentagon and domestic agencies $80 billion in debt relief in exchange for cuts elsewhere in the budget.

The deal represents one last accommodation between President Barack Obama and departing House Speaker John Boehner, but whether it succeeds depends in great measure on the reception it gets from restive House Republicans, including the arch-conservatives who forced the Ohio Republican out.

“This is again just the umpteenth time that you have this big, huge deal that’ll last for two years and we were told nothing about it and in fact even today, were not given the details,” said Rep. John Fleming, R-La. “And were probably going to have to vote on it in less than 48 hours.” A vote could come as early as Wednesday in the House.

The measure was to be discussed further at a GOP meeting this morning. Boehner hoped to get it passed before Rep. Paul Ryan’s election as his successor, expected Thursday.