WASHINGTON — Team Trump's pick for White House budget director, US Rep. Mick Mulvaney, has a track record of fighting the use of the Pentagon's war account to skirt budget caps.

Mulvaney, R-S.C., over the last two years led an alliance of Republican deficit hawks and liberal Democrats in the House pushing back on what they saw as abuses of the overseas contingency operations (OCO) account. 

Budgeteers have used the account as a relief valve for non-emergency funds, fueling criticism that it has become a slush fund.

President-elect Donald Trump tapped Mulvaney on Saturday.

Though some members of the House Freedom Caucus have shown some flexibility on defense spending, not so much Mulvaney. A member of the fiscally hawkish group, Mulvaney for the second year in a row co-sponsored an amendment to the annual defense policy bill rebuking the practice. 

"I've worked for many years to bring attention to the slush fund that is the War Budget," Mulvaney said in a May 19 press release. "It's past time to do away with the slush fund entirely. While this amendment doesn't go that far, yet, I'm proud to work with my colleagues to at least bring some accountability to how the Pentagon spends taxpayer dollars right now."

Mulvaney's co-sponsors included Reps. Chris Van Hollen, D-Md., the ranking member of the House Budget Committee; Barbara Lee, D-Calif., and Mark Sanford, R-S.C.

Combined with Trump's recent messages on social media disparaging cost overruns on the F-35, one Democratic House staffer predicted Mulvaney, leading OMB, would be Trump's "attack dog" against high-profile programs with significant overruns.

"Tweeting that these multibillion-dollar programs are over-budget really riled up his base," the staffer said of Trump. "This fits with Trump's overall narrative that you, the taxpayer, are getting screwed."

Gordon Adams, who oversaw defense budgeting for the Clinton administration, said while Mulvaney is likely to be tougher on OCO, he will have an uphill climb trimming defense overall. Trump has said publicly he wants to lift statutory budget caps, and both Vice-President-elect Mike Pence and defense secretary nominee retired Marine Corps Gen. Jim Mattis are likely to want defense increases.

"The stars are not aligned for disciplining the defense budget," Adams said. "It's sad, because it should be disciplined."