Corrected, 3:35 p.m. | When former President Donald Trump held up military aid to Ukraine in 2019, the Government Accountability Office said he violated budget law by not abiding by the will of Congress.

Now, the same issue — the freezing of appropriated funds — could trip up President Joe Biden.

As soon as next month, the Government Accountability Office will issue an opinion on the legality of Biden’s decision to hold up more than $1 billion in construction funding for a southern border wall.

The GAO, the investigative arm of Congress, began work on the opinion after Republican lawmakers accused Biden of breaking budget law by stopping construction of the border wall and pausing the obligation of the funds.

“We do have right now, pending, a decision that we’re working on,” said Edda Emmanuelli Perez, the GAO’s deputy general counsel, who testified Thursday at a House Budget Committee hearing. She said GAO asked the Office of Management and Budget and the Department of Homeland Security to provide factual and legal views to the GAO, “and we’re expecting their responses right now mid to late next week.”

Even before lawmakers requested an opinion in March, Perez said, the GAO began to explore the withholding of funds after Biden paused construction of the border wall on his first day in office. The administration said it wanted a chance to conduct a study of alternative uses for the funds.

Biden opposed the wall during his campaign and on Jan. 20 signed a proclamation ending the national emergency that Trump declared on the southern border. The Biden pause freezes whatever is left of a $1.4 billion appropriation for wall construction for the current fiscal year, as well as funds that were shifted from other accounts and any other remaining balances.

In Trump’s case, the freezing of Ukraine aid helped lead to his first impeachment, after lawmakers discovered he held up the money Congress appropriated at the same time he asked for a “favor” from Ukraine’s president to investigate Biden and his son, Hunter. The Senate acquitted him of the impeachment charges.

No one has suggested Biden is at any risk of impeachment from a Democratic Congress over a border wall funding freeze. And the administration is free to ignore a GAO opinion, which has no legal force.

But the case nonetheless raises similar questions over the president’s ability to “impound,” or withhold, funding appropriated by Congress, under the 1974 budget act that established the modern budget process. Trump’s use of the impoundment power led Democratic lawmakers to introduce legislation last year aimed at reining in the president’s authority and making the process more transparent.

“I believe in this good government legislation, and I am fully committed to pursuing its reforms regardless of who is in the White House,” House Budget Chairman John Yarmuth, D-Ky., said in opening his panel’s hearing Thursday aimed at reasserting the congressional “power of the purse.”

The Biden hold has now gone on for 100 days, twice as long as Trump’s Ukraine withholding. But the Trump pause occurred later in the year, when the funds risked expiring.

Trump administration officials said OMB withheld hundreds of millions of dollars in Ukraine aid to determine the best use of the money. A portion of the funds remained unobligated at the end of the fiscal year, leading Congress to extend the deadline for obligating the money through a rescission and reappropriation.

As part of his directive, Biden ordered administration officials to assess the legality of wall funding, contracting methods, and the consequences of ceasing wall construction, and to prepare a plan for redirecting funding and repurposing contracts. The plan was supposed to be completed within 60 days, which was March 21. Administration officials said after the self-imposed deadline passed that they are still working on the plan.

Mark R. Paoletta, who served as general counsel of OMB under Trump, defended Trump’s hold as legal but said Biden’s hold is illegal.

“What’s happening with President Biden’s hold is that he is specifically thwarting the appropriation,” Paoletta said at the hearing. Biden “wants to defy the law in implementing that program,” he said.

Several witnesses expressed general support for Yarmuth’s legislative proposals, which would require OMB to make public its apportionment of appropriated funds, among other requirements.

“Rebalancing of that power is long overdue,” said Liz Hempowicz, director of public policy at the Project on Government Oversight. She said Congress should require more transparency from OMB. 

This report has been corrected to reflect that a portion of the Ukraine aid remained unobligated by the end of the fiscal year.