Acting Defense Secretary Patrick Shanahan has approved the transfer of up to $1 billion from military personnel funds to the Army Corp of Engineers for use on the border. The transfer nearly doubles the $1.3 billion Congress authorized for border construction projects this year, though still falls short of the $5.7 billion requested by the Trump administration.

In a press release, the Defense Department said the money “will be used to support [Department of Homeland Security’s] request to build 57 miles of 18-foot-high pedestrian fencing, constructing and improving roads, and installing lighting within the Yuma and El Paso Sectors of the border in support of the February 15 national emergency declaration on the southern border of the United States.”

The transfer of funds occurs under authority of federal statute 10 U.S.C. § 284(b)(7), the press release said, which gives the Pentagon the authority to take steps to aid federal law enforcement agencies engaged in counter-narcotic activities.

House Armed Services Chairman Adam Smith (D-WA) rejected the move Tuesday. “The committee denies this request,” Smith said in a letter to Undersecretary of Defense David Norquist. “The committee does not approve the proposed use of Department of Defense funds to construct additional physical barriers and road or install lighting in the vicinity of the United States border.”

It’s not clear, however, that Congress has the authority to intervene in the matter, since the Pentagon is acting on a presidential order, and The Hill’s Ellen Mitchell said Smith’s pronouncement was “largely symbolic.” But the Pentagon could face repercussions in the future, Smith warned, saying at a hearing on the Pentagon’s 2020 budget Tuesday that “the result of that likely is that the Appropriations Committee in particular would no longer give the Pentagon reprogramming authority and I think that’s unfortunate because they need it.”

Speaking at the hearing, Shanahan acknowledged that the transfer could harm his agency in the long run. “The discussion … is that by unilaterally reprogramming, it was going to affect our ability long term to be able to do discretionary reprogramming that we had traditionally done in coordination,” Shanahan said. “It was a very difficult discussion, and we understand the significant downsides of losing what amounts to a privilege.”

“We said, ‘Here are the risks longer term to the department,’ and those risks were weighed,” Shanahan added. “And then given a legal order from the commander in chief, we are executing on that order.”