With just three weeks to the double economic hit, 22 lawmakers endorsed further cuts in projected military spending to address the nation’s debt, arguing that long-term, strategic reductions were possible with the end of the war in Iraq and the drawdown in Afghanistan.

“As we transition from wartime to peacetime, and as we confront our nation’s fiscal challenges, future defense budgets should reflect the conclusion of these wars and acknowledge that our modern military is able to approach conflicts utilizing fewer but more advanced resources,” the lawmakers wrote in a letter to Obama and congressional leaders.

The lawmakers said “substantial defense savings” could be achieved without undermining national security, and they urged Obama, House Speaker John Boehner, R-Ohio, and other congressional leaders to include such savings in any agreement.

Signing the letter were Reps. Barney Frank, D-Mass., and Mick Mulvaney, R-S.C., who earlier this year led a coalition of liberal Democrats and conservative Republicans in persuading the House to cut $1.1 billion from a $608 billion defense bill. It was the clearest signal yet that defense dollars would no longer be spared from budget cuts in a time of astronomical deficits.

Also signing the letter were Reps. Chris Gibson, R-N.Y., a member of the House Armed Services Committee, and Keith Ellison, D-Minn.

The latest Republican proposal in the negotiations with Obama calls for $300 billion in cuts in discretionary spending over 10 years, but it does not specify how much would be cut from defense and domestic programs.

The Pentagon already is facing a reduction of nearly $500 billion over a decade in projected spending, part of the budget deal that Obama and congressional Republicans agreed to in August 2011. If the two sides fail to reach an agreement to avoid the fiscal cliff, the military would face automatic, across-the-board cuts totaling $55 billion next year and close to $500 billion over 10 years.

The lawmakers wrote that they had serious concerns about those arbitrary cuts, but they support the general intent to improve the nation’s fiscal health.

“We know the United States can maintain the best fighting force in the world while also pursuing sensible defense savings,” they wrote. “How we spend our resources is just as important as how much we spend. The true foundation of our military power is not dollars or equipment, but the men and women of our armed forces, who have no equal.”

They specifically cited retired Adm. Mike Mullen, the former chairman of the Joint Chiefs of Staff, who said the single biggest threat to national security is the debt. They also pointed to the various outside organizations, conservative and liberal, that have suggested further cuts of $550 billion to projected spending.