WASHINGTON — With 15 days left in September for Congress to reach a budget agreement, five powerful military trade associations signed a letter urging congressional leadership to avoid a government shutdown or an extended continuing resolution "trap."

The five organizations are calling for a n acceptable bipartisan, multiyear deal, of the sort crafted in 2013 by Rep. Paul Ryan, R-Wis., and Sen. Patty Murray, D-Wash., which temporarily lifted spending caps for two years. The letter accused Congress of playing "the game of budget chicken," quoting recent remarks by Defense Secretary Ash Carter.

"We had hoped that meaningful negotiations would already be underway, but the media has reported little progress," the letter, dated Sept. 14, said. "Members of Congress have increasingly alluded to the possibility of an extended, or even a yearlong [continuing resolution]."

The Navy League of the United States, the National Defense Industrial Association (NDIA), the Aerospace Industries Association, the Air Force Association and the National Guard Association of the United States now join a growing chorus urging Congress to make a deal.

Before passing federal budget legislation, Congress has for years made a habit of passing short-term continuing resolutions that temporarily set spending at the previous year's levels, and — without further legislation — bar production jumps and new-start acquisition programs.

In some ways, a yearlong continuing resolution is worse than a government shutdown, the letter argues, because it "produces only more determined intransigence," while shutdowns almost always yield satisfactory budget compromises in the end.

"An extended CR would harm our national security and our economy," the letter read. "CRs may delay controversy and the inevitable trades that occur as part of budget negotiations, but they create needless and avoidable inefficiency that wastes taxpayer money. Further, a CR makes it difficult to meet ongoing operational needs, which have only become more frequent, dangerous, and pressing since the last budget deal."

At 2015 levels, the Defense Department would have a base budget of $496 billion, $3 billion shy of the $499 billion sequestration budget cap but $38 billion less than the president's $534 billion budget request for 2016.

Arnold Punaro, chairman of the NDIA's board, in a statement lamented that a continuing resolution would provide less money than sequestration levels, prolong a necessary compromise and rob the Pentagon of $3 billion a month in purchasing power relative to less than its budget request.

"A several month CR is a trap and would quickly become a yearlong CR and so Congress must avoid the temptation to kick the can down the road yet again," Punaro said.

Navy League Executive Director Bruce Butler said that many Navy, Marine Corps and Coast Guard programs would be delayed severely impacted with delays under a continuing resolution instead of an appropriations bill.

"Continuing resolution funding levels are below even the sequestration-level caps," Butler said. "At a time when we ask our sea services to do more than ever, we should not be handicapping them like this."

Air Force Secretary Deborah Lee James and Gen. Mark Welsh, Air Force chief of staff, warned last month that roughly 50 new-start programs for the Air Force are at risk if the Pentagon is forced to operate under a continuing resolution.

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