Last week, the White House announced it would extend the national emergency declaration on the southern border for another year. The move sets the stage for the White House to help itself to billions of dollars budgeted by Congress for other purposes, and instead allocate that money to building Trump’s signature border wall.

The first iteration of this plan, in 2019, was an explosive, long-lasting story. House Speaker Nancy Pelosi’s flat refusal to fund the wall—and President Trump’s last-minute decision to break with Mitch McConnell and insist on a spending agreement that did fund it—spiraled into the longest government shutdown in U.S. history. Then, Trump’s decision to go around Congress by making use of a national emergency was widely panned as an executive power grab. Majorities in both houses of Congress—including 13 Republicans in the House and 12 in the Senate—voted to overrule the president and cancel the emergency, although neither body managed to muster the two-thirds vote necessary to surmount Trump’s veto. Several legal challenges are currently working through the courts, but the Trump administration has been given the go-ahead to work on the wall in the meantime.

A year later, the public pressure is lower. The story of the emergency renewal came and went with barely a stir. And yet, this time around, some congressional Republicans are experiencing an uncomfortable epiphany: Now that Trump has gotten the green light, there’s nothing keeping him from shortchanging their priorities to scrape together the necessary funds for the wall.

Take Rep. Mac Thornberry, the ranking GOP member on the House Armed Services Committee. Thornberry was not among those who voted to oppose the national emergency last year. This time around, however, he announced his opposition to Trump’s reassignment of funds, which he said “undermines the principle of civilian control of the military and is in violation of the separation of powers within the Constitution.”

“The reprogramming announced today is contrary to Congress’s constitutional authority, and I believe that it requires Congress to take action,” Thornberry said in a statement. “I will be working with my colleagues to determine the appropriate steps to take.”

Why the change of heart? The answer is complex, but has to do with the specific funds targeted for reprogramming last year and this year. Last year, Trump cobbled together money from two different sources: an account for funding military construction and an account for drug enforcement. (So far, the White House has only announced plans to make use of the latter account, although the administration is expected to renew the former soon.)

With respect to the drug enforcement account, a source in Thornberry’s office told The Dispatch, the Trump administration did a good job last year of targeting only money that was likely to go unspent anyway, at least not until the following fiscal year. This time around, however, the Pentagon is diverting funds that were allocated by Congress to make military equipment purchases, including two Navy F-35s and two V-22 Osprey aircraft.

“It is more apples to apples to compare pulling money that could not be, and was not going to be, spent for its intended purpose last year, versus pulling money from programs earlier in the fiscal year [this year] that could be spent where Congress had directed them to spend it,” the source said.

Sources said that lawmakers were additionally unhappy because of how the Defense Department appeared to have decided which funds to tap. In several cases, Congress allocated more money for military equipment purchases than DoD had requested. The Pentagon then turned around and marked the money for such “surplus” purchases as free to be diverted toward the wall—the source of Thornberry’s “civilian control of the military” complaint.

There’s political risk for Trump in targeting military funds that will be missed in Congress. Many prominent Democrats have already suggested taking some form of action to target the president’s ability to reallocate military budgets, although nothing specific has been announced. The most likely vehicle for such action at this point would be next year’s National Defense Authorization Act, which lawmakers will begin drafting over the next few months. A spokesperson for House Armed Services Chairman Adam Smith told The Dispatch that, “Given that the NDAA process is just beginning, we are not in a position to discuss what legislative options Chairman Smith will consider to curtail actions such as these in the future.”

Another possible reform would be Sen. Mike Lee’s proposed ARTICLE ONE Act, which would target the issue from the other side: Rather than limit the amount of funds a president could access during a national emergency, Lee’s bill would cause all national emergency declarations to sunset after 30 days unless Congress voted to stretch them longer, and then require annual reauthorizations to remain extant. The bill picked up 15 GOP co-sponsors when Lee introduced it last year, but without Democratic buy-in it withered on the vine. This year, Lee hopes the proposal might get another look.

“The problem with national emergencies is way bigger than Trump’s wall,” Lee spokesman Conn Caroll told The Dispatch. “The NEA [National Emergencies Act] triggers all kinds of big powers spread throughout the federal code. The ARTICLE ONE Act addresses this problem comprehensively by ending all emergency declarations after a year without an affirmative vote from Congress.”

Photograph by Sandy Huffaker/AFP via Getty Images.