WASHINGTON – U.S. Sen. Susan Collins has signed a letter backing a bipartisan plan in the Senate that aims to cut the deficit by at least $3.7 trillion over 10 years through a mix of spending cuts and increased revenues from closing some tax loopholes.

The Maine Republican is one of 33 senators, 15 of them Republicans, to sign the letter, as the Senate searches for a compromise plan to hike the $14.3 trillion debt ceiling and avoid a federal debt default looming on Aug. 2.

The Senate is expected to vote Friday on the House GOP-approved “Cut, Cap and Balance” bill that makes large cuts to federal programs, does not increase any tax revenues and raises the debt ceiling in exchange for a balanced budget amendment that would make it very difficult to pass future tax hikes.

U.S. Sen. Olympia Snowe, R-Maine, has not signed on to the letter in support of the Gang of Six plan, and said in a statement Thursday that she has reservations about the plan, particularly in how it would recalculate cost-of-living adjustments for Social Security benefits and the pensions of military veterans.

Snowe indicated that she might vote in favor of a procedural motion allowing for a debate on the House GOP bill, because it could lead to a vote on a balanced budget amendment, which she supports.

Collins is still reviewing the House Cut, Cap and Balance bill, which will not pass the Democratic-led Senate.

But the letter Collins signed lauds the bipartisan plan devised by the “Gang of Six” senators led by Democratic Sen. Mark Warner of Virginia and GOP Sen. Saxby Chambliss of Georgia as a proposal that “strikes the necessary balance between spending cuts, tax and entitlement reform, and enforcement to constrain future spending. This is a plan that can unite Republicans, Democrats and Independents.”

The letter, sent to Senate Majority Leader Harry Reid, D-Nev., and Senate Minority Leader Mitch McConnell, R-Ky., says that the Gang of Six “has produced a framework that provides a bipartisan, comprehensive and balanced way to put our nation on a stable fiscal path.”

In the end, Congress may be heading for a short-term agreement to raise the debt ceiling before the Aug. 2 deadline, as debate continues on longer-term deals.

MaineToday Media Washington Bureau Chief Jonathan Riskind can be contacted at 791-6280 or at: jriskind@mainetoday.com