Senate Republicans intend to block action on virtually all Democratic-backed legislation unrelated to tax cuts and government spending in the current postelection session of Congress, officials said Tuesday, adding that the leadership has quietly collected signatures on a letter pledging to carry out the strategy.

If carried out, it would doom Democratic-backed attempts to end the Pentagon's practice of discharging openly gay members of the military service and give legal status to young illegal immigrants who join the military or attend college.

Senate Majority Leader Harry Reid has made both measures a priority as Democrats attempt to enact legislation long sought by groups that supported them in the recent midterm elections.

A nuclear arms treaty with Russia that President Barack Obama wants ratified would not be affected, since any debate would take place under different rules than those that apply to legislation. Even so, its passage is not assured as Republicans are seeking concessions from the White House.

Officials who disclosed the new Republican maneuver did so on condition of anonymity, saying they were not authorized to discuss it.

It was not known how many of the Senate's 42 Republicans had signed the draft letter, which the leadership intends to make public quickly.

Senate Democrats need 60 votes to overcome any delaying tactics, meaning they could be thwarted if 41 Republicans join in the commitment.

Democrats' chances of passing politically charged legislation will dim when the new Congress convenes in January, since Republicans will take control of the House and gain more Senate seats.

The letter comes after comments by Senate Republican Leader Mitch McConnell and others in his party that the voters made it clear in the elections they want lawmakers to focus on economic issues.

"Despite what some Democrats in Congress have suggested, voters did not signal they wanted more cooperation on the Democrats' big-government policies that most Americans oppose," McConnell and incoming House Speaker John Boehner, R-Ohio, wrote in an op-ed article published in the Washington Post.