Judge Emmet Sullivan was at the heart of Michael Flynn’s dramatic sentencing hearing Tuesday, once again delaying it.

Sullivan tore into Flynn, President Trump’s former national security adviser, telling him he couldn’t hide his “disgust” or “disdain.”

“Arguably, you sold your country out,” Sullivan told Flynn.

The 71-year-old judge also questioned whether Flynn committed treason before he walked back those comments. He said he wasn’t suggesting Flynn did, in fact, commit treason but asked prosecutors about the potential crime because he was “just curious.”

“After looking at the definition of treason, we have no reason to believe he committed treason,” prosecutors said.

Read on for a look at five things to know about Sullivan.

He’s involved in another Trump-related lawsuit

Earlier this year, Sullivan gave an assist to Democrats suing Trump over claims he violated the U.S. Constitution’s emoluments provision banning the acceptance of gifts and foreign domestic interests through his hotel business and other properties.

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Sullivan’s ruling didn’t find Trump guilty of wrongdoing but instead allowed Democrats to continue their case in the courtroom, where they would have to make a case that he did.

He’s been appointed to positions by both Republicans and Democrats

Sullivan was nominated to the U.S. District Court for the District of Columbia in 1994 by former President Bill Clinton. He was confirmed later that year.

Prior to that, Sullivan was nominated to the District of Columbia Court of Appeals in 1992 by former President George H.W. Bush. In 1984, he was nominated to the Superior Court of the District of Columbia by former President Ronald Reagan.

He made news with an asylum case earlier this year

Sullivan made national headlines in August after he learned a mother and daughter had been deported despite being their asylum claim being before him, according to The National Law Journal.

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He reportedly ordered the government to “turn that plane around either now or when it lands.”

If the government would not comply, he threatened to summon then-Attorney General Jeff Sessions, Homeland Security Secretary Kirstjen Nielsen and other officials to court to “SHOW CAUSE why they should not be held in CONTEMPT OF COURT,” NBC News reported in August.

He tossed former Sen. Ted Stevens corruption case

Sullivan presided over the federal corruption case involving the late Republican Sen. Ted Stevens and ultimately threw it out. Sullivan reportedly chastised the prosecutors in the 2009 case for “mistakes” they made in the case.

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“For 25 years I’ve told defendants they’d receive a fair trial,” Sullivan said at the time. “I’ve never seen such mishandling or misconduct.”

He’s a graduate of Howard University

Sullivan is a two-time graduate of Howard University. He received a bachelor’s degree in 1968 and a law degree in 1971.

He clerked for Judge James Washington of the Superior Court of the District of Columbia before going into private practice for a decade.

Fox News’ Lukas Mikelionis, Alex Pappas and The Associated Press contributed to this report.