Donald Trump’s former chief of staff Mark Meadows has sued House Speaker Nancy Pelosi (D-CA) and the House Select Committee investigating the Jan. 6 Capitol riot in an attempt to skirt testifying before the panel.

The move comes the same day the committee indicated it would move forward with contempt charges after Meadows didn’t show up for his scheduled deposition.

Meadows’ attorneys wrote in the suit, filed in Washington D.C. federal court on Wednesday, that if Meadows does comply with the committee’s request, he would be “illegally coerced into violating the Constitution.” He’s also suing to block a subpoena for his phone records issued to Verizon, his cell phone carrier, in November.

“The Select Committee wrongly seeks to compel both Mr. Meadows and a third party telecommunications company [Verizon] to provide information to the Select Committee that the Committee lacks lawful authority to seek and to obtain,” his lawyers said. They alleged the committee’s subpoena would “violate longstanding principles of executive privilege and immunity.”

Rep. Adam Schiff (D-CA), who sits on the committee, responded, “It strikes me as another frivolous effort to impede the work of the committee.”

Trump has directed his lieutenants not to speak to the congressional committee about Jan. 6, asserting that executive privilege shields him and his associates from lawmakers’ subpoenas. He sent a letter to that effect to Meadows on Oct. 6, according to the suit. President Joe Biden, however, has indicated he will not direct the Justice Department to support Trump’s claim. As a result, Meadows argues he is caught between a rock and a hard place, put in the “untenable position of choosing between conflicting privilege claims.” Courts have also denied Trump’s requests for injunctions against the National Archives releasing records from the Trump White House.

Meadows agreed just last week to sit for a deposition before the panel of lawmakers, but he reversed course Tuesday. He has already turned over thousands of pages of documents, including some unflattering text messages, but his lawyers say he pulled out because the panel wanted to probe privileged matters. The committee has interviewed nearly 300 witnesses in its investigation of the attempted insurrection.

The suit describes in play-by-play detail the negotiations between Meadows and the committee over his testimony. Committee chairman Rep. Bennie Thompson (D-MS) wrote to Meadows’ lawyer, George Terwilliger, on Tuesday, “The select committee is left with no choice but to advance contempt proceedings and recommend that the body in which Mr. Meadows once served refer him for criminal prosecution.” Meadows named Thompson as a defendant in his lawsuit.

Documents filed in court along with the lawsuit showed that Terwilliger has been writing to the White House as far back as early October, when he told Biden administration lawyers that his client “asserts no personal stake” in the records that investigators are seeking. But Terwilliger also defended Meadows’ reluctance, saying that Trump’s former chief of staff “wants to ensure that the institution of the Presidency is protected and that the long-standing traditions which protect its operations are not traded away for political expediency.”

A Nov. 3 letter from Terwilliger to the committee foreshadowed that Wednesday’s lawsuit was coming, and it also indicates that Meadows plans to take his legal fight to the nation’s higher courts.

“Mr. Meadows would resist being so compelled unless and until a court orders him to do otherwise, including after full appellate review,” his lawyer wrote to the committee last month.

In another letter, Terwilliger warned this legal fight “could take a substantial amount of time and resources.” It’s widely suspected that Trump loyalists are engaged in a united effort to delay the committee’s work until the end of 2022, when the midterm elections could put Republicans in charge who could potentially end the investigation.

In fact, at one point the committee wrote to Meadows to make that accusation head on.

“This history has led the Select Committee to suspect that you are simply engaged in an effort to delay, and that Mr. Meadows has no genuine intent to offer any testimony on any relevant topic,” reads a Nov. 22 letter signed by Rep. Thompson.

Now public as well are the committee’s letters to Meadows, in which the former right-hand man to Trump is told that the investigators plan to question him about the previous administration’s conspiracy-drenched “Stop the Steal” campaign, the scheme to use the Justice Department to perpetuate fake election fraud claims, and “efforts to pressure state and local officials and entities… to challenge the results of the presidential election.”

The committee is also keenly interested in whether Meadows used encrypted apps on his computer and phone to communicate about government matters during the last three months of the Trump administration—and whether he used personal devices and email accounts. Investigators are currently gathering mountains of data from the National Archives and witnesses, combing through it all to piece together what role, if any, Trump’s White House played in instigating the Jan. 6 insurrection.

Notably, Meadows was instrumental in putting together the infamous Jan. 2 call between Trump and Georgia’s top elections official, when the president asked the peach state’s secretary of state, Brad Raffensperger, to “find 11,780” votes to reverse his loss to Joe Biden.

Although Meadows has apparently been willing to answer select questions in writing, these letters show that Trump’s one-time lieutenant isn’t willing to talk about how Trump planned to use the Justice Department or the White House’s actual understanding about supposed election fraud. And the committee complained when he had “not produced even a single document” as of mid-November.

Days later, letters show, Meadows turned over 6,836 pages of relevant documents from his personal Gmail account. The next week, he gave up an additional 2,514 pages of material—backups from his personal cell phone.

Former Trump chief strategist Steve Bannon was indicted for contempt in November after declining to testify before the panel. The committee has also voted to pursue charges against Jeffrey Clark, a Justice Department lawyer who pushed the agency to investigate Trump’s baseless claims of voter fraud in the 2020 presidential election.

“There is no legitimate legal basis for Mr. Meadows to refuse to cooperate with the select committee and answer questions about the documents he produced, the personal devices and accounts he used, the events he wrote about in his newly released book and, among other things, his other public statements,” Thompson wrote.

Contempt charges for Meadows, Trump’s chief of staff at the time of the riot, would escalate the stakes of the legal battle over the investigation. Bannon, by contrast, was not working for the Trump administration on Jan. 6.