WASHINGTON — Meet the new budget fight, same as the old budget fight. If Republicans want more money for defense, Democrats will insist on extra funds for non-military programs too.

Parity, a key part of Democrats' negotiating position in last year's bipartisan budget agreement, is again a watchword, according to Senate Appropriations Vice-chair Barbara Mikulski, D-Md. That's whether Senate Republicans seek to add to the Pentagon's fiscal 2017 budget through the Overseas Contingency Operations account, or otherwise.

"No matter what they do, we want parity," said Mikulski, a key player in negotiating last year's budget deal. "A budget deal is a budget deal, and if they want to add to defense and use OCO to do it, we stick to our three principals: Parity between defense and non-defense, reasonable allocations and no poison pill riders."

Though Republican senators have been vague about the prospect, Mikulski said she expects them Republicans to seek more defense spending — not as appropriators mark up their bills this month, but when those bills come to the floor later this year, a prediction based on previous "patterns of behavior."

Mikulski said that she expects subcommittee allocations, known as 302(b)s, to be disclosed April 14, kicking off the upper chamber's appropriations process.

On the House side, leadership is seeking a fiscal 2017 budget resolution in line with last year's budget deal between President Barack Obama and former House Speaker John Boehner, R-Ohio, which calls for $1.07 trillion in spending next year. But budget hawks in the House Freedom Caucus are seeking a $30 billion budget cut — an impasse that has yet to be resolved.

That proposal sets $574 billion in base budget requirements, with some funded through the base budget and some through the OCO budget. That leaves OCO funding $18 billion short of the activities the president has asked for, according to House Armed Services Chair Mac Thornberry — something the next Congress and administration may reconcile through a notional emergency supplemental.

A former senior House appropriator, Jim Moran, said he expects House appropriators to again seek again an add for defense through OCO. DoD’s list of "unfunded priorities," passed over in President Obama’s 2017 budget request, could be their guide. 

"OCO is the fudge factor, everybody knows that, but a lot of the programs you're looking at are for combat overseas, so they qualify under the OCO rubric," said Moran, now senior legislative adviser at the Washington, D.C.-based McDermott Will & Emery law firm and a lobbyist for General Dynamics and Boeing.

The tug of war over defense and non-defense spending led to a protracted stalemate last year, and analysts are already predicting this year's dynamics will follow a familiar pattern. Regular appropriations will founder, ultimately necessitating a continuing resolution to fund the government this fall.

Back on the Senate side, Sen. Richard Shelby, R-Ala. and a member of the Appropriations Defense Subcommittee, said he expects the committee to discuss whether to raise defense spending though OCO. Yet he was unsure whether there was enough political will among Senate Republicans to win the fight that would ensue.

"There's a need, but there's a question of whether there's a political will—we'll have to test that," Shelby said. "I just came out of a classified hearing with [Director of National Intelligence James Clapper] talking about our challenges in the world. I wish the people could hear that. They would see we need to beef up our military everywhere."

Armed Services Chairman John McCain, R-Ariz., was noncommittal about OCO as the means he might use in an attempt to raise defense spending, saying, "we are looking at a number of options."

When the SASC marks up its defense policy bill next month, the 2017 National Defense Authorization Act, it is unclear what top-line the defense policy bill will use, McCain said. He said he expects to resolve the question in talks with the committee's top Democrat, Sen. Jack Reed, of Rhode Island.

"I'm having final discussions with Jack Reed," McCain said. "As you know, he's always had a different point of view of this OCO thing. We're trying to come to an agreement. I don't know if we will or not."

Last year, Reed opposed the 2016 NDAA because it affirmed the transfer of $39 billion from the proposed base budget to OCO. He condemned the move as "an off-budget gimmick" to skirt statutory budget caps.

Reed, this week, said the top-line set by the Senate Appropriations Committee matters most, and the first step will be to look at that.

"Once we have that number, the authorization bill can express a different view, but the appropriations will be appropriated to that number," he said.

Another Democrat on the SASC, Claire McCaskill, said adding defense dollars and getting the necessary votes, "would be very difficult to do," and require consensus on domestic priorities.

McCaskill, who represents Missouri, home to Boeing's US headquarters, expressed sympathy for the idea of raising defense spending. On the heels of an overseas trip, she said Russia's recent activities highlight the need for a more robust military.

"So there are real needs in the military that I feel very strongly about, but I also know my Democratic colleagues are not going to be excited about busting the [budget] caps, if we're not doing anything on the other side of the equation," McCaskill said. "Especially homeland security, airport security and all those things we have to work on."

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