As part of their investigation into the violence in the US Capitol, the House Select Committee has decided to subpoena former President Donald Trump.

Although it doesn’t happen often, Congress has had success in calling both current and former presidents to testify.

Also read: Jan 6 hearings: Lofgren says Trump planned with Tom Fitton to declare premature victory

The unanimous vote represents a step up in the committee’s efforts to summon the former president for testimony, even though it’s unlikely that Trump would do so at this point and the committee probably doesn’t have time for a protracted legal battle.

Democratic Rep. Bennie Thompson, the committee’s head, revealed at the start of the hearing that the committee had turned Thursday’s public hearing into a business meeting, a technical distinction that allows the committee to vote on investigative measures.

Also read: Alyssa Farah Griffin, former White House aide says Trump ‘wholly unfit’

“It is our obligation to seek Donald Trump’s testimony,” Thompson said before the vote. “There is precedent in American history for Congress to compel the testimony of a President. There is also precedent for presidents to provide testimony and documentary evidence to congressional investigators.”

“We also recognize that a subpoena to a former president is a serious and extraordinary action,” Thompson added.

At the end of this congressional term, the subpoena will become inactive.

Also read: January 6 hearing Day 9: Liz Cheney says Donald Trump was ‘central cause’ of Capitol attack

The committee, according to Thompson and vice chair Liz Cheney, needs to hear from Trump in order to provide the most thorough account it can of the violence on January 6.

“Thanks to the tireless work of our members and investigators, we have left no doubt — none – that Donald Trump led an effort to upend American democracy that directly resulted in the violence of Jan. 6,” Thompson said, adding, “He is the one person at the center of the story of what happened on Jan. 6. So we want to hear from him.”

Also read: Jan 6 hearing: Why the 9th hearing is important

Invoking their Fifth Amendment privilege against self-incrimination, more than 30 witnesses, according to Cheney, including several who spoke with Trump, have done so. She claimed that the committee couldn’t wait for the Justice Department to get information from those obstinate witnesses, pointing out that others, like Steve Bannon, had been found in contempt of Congress for refusing to testify; Bannon was convicted after the Justice Department indicted him.

Also read: Capitol riots hearing to posit Donald Trump as ‘clear, present danger to democracy’

“At some point, the Department of Justice may well unearth the facts that these and other witnesses are currently concealing,” Cheney said.

“But our duty today is to our country and our children and our Constitution. We are obligated to seek answers directly from the man who set this all in motion. And every American is entitled to the answers, so we can act now to protect our republic,” she added.