The subpoena comes just days after special counsel Robert Mueller’s report revealed that McGahn witnessed and testified about potential obstruction of justice by the president.

The committee is seeking to secure McGahn’s testimony as part of its investigation into the president, which kicked off last month with requests for documents and witness testimony from 81 people and entities associated with Trump. On Sunday, Nadler (D-N.Y.) said he intended to call McGahn to testify before the committee; on Monday, he made it official, asking McGahn to turn over documents by May 7 and testify two weeks later.

“The Special Counsel’s report, even in redacted form, outlines substantial evidence that President Trump engaged in obstruction and other abuses,” Nadler said in a statement Monday. “It now falls to Congress to determine for itself the full scope of the misconduct and to decide what steps to take in the exercise of our duties of oversight, legislation and constitutional accountability.”

McGahn has emerged as a central witness in the Judiciary Committee’s obstruction probe. He told Mueller’s investigators that Trump ordered him to fire the special counsel but that he refused the directive. The incident was first reported by The New York Times in January 2018.

According to McGahn, Trump told him: “You gotta do this. You gotta call [Deputy Attorney General] Rod [Rosenstein].” Trump later said, according to McGahn: “There are conflicts. Mueller has to go.” Trump tried to persuade McGahn to publicly deny the Times story, but McGahn refused because he said the Times story was accurate. Trump later tried to get McGahn to memorialize a denial of the incident internally; McGahn again refused.

“Mr. McGahn is a critical witness to many of the alleged instances of obstruction of justice and other misconduct described in the Mueller report,” Nadler said. “His testimony will help shed further light on the president’s attacks on the rule of law, and his attempts to cover up those actions by lying to the American people and requesting others do the same.”

Mueller decided not to accuse Trump of obstructing justice, even though he described multiple instances in which the president met the criteria for committing the crime. Mueller, though, cited the guidelines from the Justice Department Office of Legal Counsel stating that a sitting president cannot be indicted and said even informally suggesting Trump obstructed justice would be unfair outside the bounds of a traditional prosecution. Mueller said Trump repeatedly tried to “influence” the investigation but added that those attempts were unsuccessful because top aides such as McGahn refused to carry out his commands.

Despite Trump’s claims of “total exoneration,” Mueller specifically said his report “does not exonerate” the president of obstruction.

“If we had confidence after a thorough investigation of the facts that the president clearly did not commit obstruction of justice, we would so state,” Mueller wrote in his report.

Attorney General William Barr also decided against charging Trump with obstruction. Democrats have taken aim at Barr in recent days, accusing him of misleading the public about Mueller’s investigation and using his perch to spin Mueller’s findings in Trump’s favor.

Rep. Doug Collins of Georgia, the top Republican on the Judiciary panel, denounced the McGahn subpoena as frivolous.

“Don McGahn sat for more than 30 hours of interviews with the special counsel’s investigation, and the chairman has answered that with a stunning 36-item subpoena,” Collins said. “Instead of looking at material that Attorney General Barr has already made available, Democrats prefer to demand additional materials they know are subject to constitutional and common-law privileges and cannot be produced.”

The subpoena comes as Democrats grapple with whether to launch impeachment proceedings against Trump. Speaker Nancy Pelosi, who has said she opposes impeaching Trump, wrote in a letter to House Democrats earlier Monday that “the facts regarding holding the president accountable can be gained outside of impeachment hearings.”

Monday’s subpoena for McGahn was not the first Nadler has issued since a redacted version of Mueller’s report was released on Thursday. The next day, Nadler subpoenaed the Justice Department for the full, unredacted report and all its underlying evidence.