WASHINGTON -- Armies of lawmakers from both parties are sending signals that they stand ready to back a bipartisan deficit reduction compromise, giving President Barack Obama and House Speaker John Boehner an instant base of support if they can reach an agreement.

Rank-and-file members of the Senate and House of Representatives from both parties have been meeting privately to discuss cooperation. They’re not talking specifics. Their aim is to provide, sometimes in writing, assurance that if negotiators hammer out an agreement perceived as fair, “we’ll have their back,” said Rep. Heath Shuler, D-N.C., one of the effort’s organizers.

Obama and congressional leaders are expected to resume talks shortly aimed at avoiding the “fiscal cliff.” Bush-era tax cuts are set to expire at the end of this year, and $109 billion of automatic spending cuts are due to take effect Jan. 2 unless negotiators – and Congress – agree on an alternative.

In the House, about 20 lawmakers met Nov. 16, the same day Obama, Boehner and other leaders were holding their first negotiating session. The lawmakers discussed a letter they would circulate among colleagues, saying that “to succeed, all options for mandatory and discretionary spending and revenues must be on the table.”

The letter, whose chief backers include Shuler and Reps. Mike Simpson, R-Idaho, Jim Cooper, D-Tenn., and Steven LaTourette, R-Ohio, makes no mention of the key flashpoints, such as raising income tax rates on the wealthy, a problem for many Republicans, or tinkering with Medicare and Social Security, a problem for Democrats.

That general but genial tone is the letter’s strength, said Simpson, and “with enough members signed on, we believe it sends a very powerful message.”

The letter quickly got about 30 signatures when it was circulated just before Congress left for its Thanksgiving recess Nov. 16.

A similar letter last year to the congressional “supercommittee,” which tried but failed to find $1.2 trillion worth of deficit reduction, got 102 House signatures. A Senate letter urging bipartisan cooperation was signed by 45 members. Shuler saw the signatures from members of both parties as evidence that bipartisanship was possible, particularly since the letter was circulated as members of Congress were about to face primaries and caucuses.

The new letter tries to reassure Obama and Boehner that a bipartisan deal could start with a strong base of support. Shuler showed the letter to Boehner, who offered his encouragement.

Boehner for years was regarded as a leader willing to compromise, but he has had trouble in recent years as the Republicans, who currently have a 241-193 House majority, became more dominated by diehard conservatives reluctant to deal with Democrats.

A bipartisan base of support could be important, since budget deals usually need backing from members of both parties. In the Senate, 60 votes are needed to cut off debate, and Democrats now control 53 of the 100 seats.

The summer 2011 package that avoided default and raised the nation’s debt ceiling won the backing of 95 Democrats and 174 Republicans in the House and 45 Democrats, 28 Republicans and one independent in the Senate.

“The bipartisan groups can be meaningful in getting something enacted. It would keep up the momentum,” said Robert Bixby, executive director of the Concord Coalition, a nonpartisan budget watchdog group.