UPDATE (6/4/2021 5pm EST): House Judiciary Chairman Jerry Nadler, who is overseeing the closed door testimony, says McGahn has been “somewhat difficult.” McGahn was accompanied by two GOP congressman: Reps. Jim Jordan of Ohio and Matt Gaetz of Florida. Both House members are know for their combative style and extreme deference toward Donald Trump. Continue reading below for full context.

For over two years, Congressional Democrats have wanted to speak with Don McGahn, the Trump White House Counsel who was a key witness in the Mueller investigation.

On Friday, they’ll finally have their chance. McGahn is scheduled to testify before the House Judiciary Committee and he’ll likely encounter questions about the former president’s alleged effort to obstruct Mueller’s inquiry, which examined potential ties between the 2016 Trump campaign and Russian operatives.

But for many, McGahn’s appearance is too little, too late. His testimony will take place behind closed doors and a transcript will only be made public after it has been approved by his lawyers. Questions are limited to topics contained in the redacted version of Mueller’s report, which means other scandals from the Trump era are off the table.

The court battle over McGahn’s congressional appearance has dragged on for two years. He – and the Trump administration – initially claimed that he was exempt from a Congressional subpoena because he was a high-ranking White House official. The Biden Justice Department finally reached a deal with McGahn last month. As NPR puts it, the agreed to terms “raises questions about how much the committee and the American people will learn from McGahn’s interview beyond what’s already publicly known.”

Over the course of five meeting with investigators, McGahn delivered some of the most eyebrow raising testimony contained in the Muller report. From CNN:

Between 2017 and 2019, McGahn told the special counsel he refused to follow the President’s directions to fire Mueller “deciding that he would resign rather than trigger what he regarded as a potential Saturday Night Massacre,” Mueller’s report said, referring to one of the darkest periods of the Nixon presidency during the Watergate scandal. Trump also told McGahn to deny he had tried to fire Mueller, but the lawyer wouldn’t do it, according to the Mueller report.