WASHINGTON — Acting U.S. Defense Secretary Patrick Shanahan has a lot of explaining to do, say key lawmakers who worry the Trump administration is keeping Congress in the dark as the White House works to divert military funds toward building barriers on the U.S.-Mexico border.

In a letter to Shanahan made public Friday, a group of five House Democrats led by Armed Services Committee Chairman Adam Smith, D-Wash., and Appropriations Committee Chairwoman Nita Lowey, D-N.Y., demanded Shanahan turn over an exhaustive trove of documents from 25 categories related to President Donald Trump’s national emergency declaration.

In and out of the public eye, lawmakers have met with the Pentagon officials sent to defend the administration’s plans — acting Deputy Defense Secretary David Norquist and Assistant Secretary of Defense for Sustainment Robert McMahon — and come away fuming that details of Pentagon deliberations are being withheld and fearful Shanahan may take action without informing Congress.

“While the President has issued a national emergency proclamation, our committees are still responsible for performing their constitutional oversight responsibilities,” the lawmakers wrote. “As such, given the speed with which we believe the Department of Defense may be acting in response to the emergency proclamation, we request that you produce the requested documents and information no later than March 21, 2019.”

The letter asks that the Pentagon commit to warning Congress 60 days before shifting any funds toward border wall construction.

Loaded with bullet points, their six-page document request also puts a heavy burden on Shanahan and other military officials to explain and justify the movement of funds from the handful of categories, particularly the most politically sensitive of them all — military construction.

The letter was also signed by House Appropriations Subcommittee on Defense Chairman Pete Visclosky, D-Ind.; House Appropriations Subcommittee on Military Construction, Veterans Affairs, and Related Agencies Chairwoman Debbie Wasserman Schultz, D-Fla.; and House Armed Services Readiness Subcommittee Chairman John Garamendi, D-Calif.

Next week, the Republican-controlled Senate is poised to pass a resolution that would cancel Trump’s national emergency. The House passed the resolution, and four Republican senators have said they will cross party lines to send the resolution to the president — which would bait his veto.

The national emergency declaration was intended to let Trump bypass Congress and fund a border wall with $1.4 billion appropriated by Congress, $3.1 billion in Treasury and DoD counter-drug funding — and after those are exhausted, military construction dollars.

Writing in Politico this week, Gordon Adams, a White House budget official from the Clinton administration, said that beyond lawmakers’ concerns their constitutional powers are being usurped are their concerns about the economic and political impact of canceling construction projects back home.

“Those trivially small projects, most of them well under $35 million, are one of the most precious pieces of pork in the budget,” Adams wrote. “Members of Congress fall over themselves to protect and enhance a local base. Military construction dollars are a key part of their effort.”

At the same time, lawmakers fear Pentagon leaders will abandon the practice of formally asking for authority to shift funds between accounts and simply put them in the counter-drug account.

“We are similarly frustrated by the lack of transparency from the Department of Defense with respect to the planning and use of section 284 [counter-drug] authority, as well as the disregard for decades of precedent with regard to congressional oversight of the transfer of authorized and appropriated funds,” the March 7 letter reads.

Smith, earlier in the week, threatened that Democrats would strip the Pentagon of its ability to shift funds within its budget next year if it doesn’t get approval from the congressional defense committees first.

“My concern is not where it is coming from,” Smith told Military Times on Friday. “My concern is where it is going: to something that has nothing to do with the national security of this country and where we should not be spending money.”

The concern is coming from both sides of the aisle.

“Not following the practice that has been followed by decades will affect the relationship between the legislative branch and executive branch," said HASC ranking member Mac Thornberry, R-Texas. "There will be a reaction, and it will make it harder to reprogram in the future to meet emerging needs.”

Joe Gould was the senior Pentagon reporter for Defense News, covering the intersection of national security policy, politics and the defense industry. He had previously served as Congress reporter.

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