As the Department of Government Efficiency rapidly moves to reshape the federal government, several groups challenging DOGE in court are attempting to determine how Elon Musk’s budget-slashers were able to rapidly entrench themselves in at least 15 agencies.

Over the coming week, federal judges have ordered key Trump administration officials to testify about mass firings and the dismantling of key agencies, while DOGE representatives will likely have to turn over evidence in dozens of cases and participate in a sworn deposition for at least one case.

The legal challenges materializing against DOGE could present an existential challenge for the group, whose effectiveness has in part stemmed from its ability to move quickly and make massive changes without the normal oversight.

While Musk and Trump have touted DOGE’s transparency — including on DOGE’s website, where it lists recently canceled contracts — the plaintiffs challenging the group have argued that the group has relied on secrecy to hide tactics that violate federal law.

“[T]he entity has worked in the shadows — a cadre of largely unidentified actors, whose status as government employees is unclear, controlling major government functions with no oversight,” one lawsuit alleged.

That secrecy has also made it harder for nonprofits or federal unions to successfully block DOGE in court, with many plaintiffs relying on media reporting — rather than documentary evidence — to prove the harms DOGE has allegedly caused.

“The court can’t act based on the media reports. We can’t do that,” one federal judge said in a case about the constitutionality of Musk’s power. “The things that I’m hearing are concerning indeed and troubling indeed, but I have to have a record, and I have to make a finding the facts before I issue something.”

But that might begin to change as the cases against DOGE progress and plaintiffs are entitled to receive discovery — i.e., the exchange of evidence — relevant to key allegations. At least one federal judge has ordered a DOGE representative to sit for a sworn deposition about the group’s access to the federal government’s sensitive data.

A federal judge in Washington, D.C, was scheduled Friday afternoon to consider what kind of regulations will govern the transparency behind DOGE after the group argued it shouldn’t be subject to the Freedom of Information Act, and next week might provide some of the first sworn testimony about Trump’s effort to rapidly reduce the size of government since retaking office.

On Monday, a federal judge in Washington is holding a hearing at which the acting chief operating officer of the Consumer Finance Protection Bureau has been ordered to testify about the ongoing dismantling of the agency, and a separate judge in California on Thursday is requiring the acting director of the Office of Personnel Management to testify under oath about how the Trump administration allegedly ordered the mass firing of probationary employees.

“We will prove in this case that remarkably, and I do not say this lightly, your honor, Acting Director [Charles] Ezell is not telling the truth to this court,” a lawyer challenging the mass firings alleged, prompting the judge overseeing the case to order Ezell to testify in person.

“We’re going to have Ezell come out here and he’s going to be under oath right up there and these lawyers are going to quiz him,” U.S. District Judge William Alsup said.

During a court hearing on Thursday about Ezell’s testimony, lawyers with the Department of Justice said the administration is considering making Ezell unavailable for testimony despite the court’s order, citing logistical concerns and their potential appeal of the decision. Lawyers for the plaintiffs called the move a clear defiance of a court order and a delay tactic.

“No final decision had been made,” a DOJ lawyer told Judge Alsup, suggesting the final decision would be made in Washington.

The Trump administration has already begun its appeal in more than a dozen cases challenging Trump’s executive actions, and two adverse rulings have already reached the Supreme Court.