Matthew Petersen, a nominee to be a judge at the federal district court in Washington, D.C., is a former chief counsel to a Senate committee and a Federal Election Commission commissioner, which is why his failure to answer basic legal questions in a hearing this week made headlines.

Petersen, nominated by President Donald Trump in September, was rated ”qualified” by the American Bar Association. Yet, faced with a pop quiz in his Senate confirmation hearing Wednesday from Sen. John Kennedy, R-Louisiana, Petersen was unable to answer basic legal questions. Asked to define a “motion in limine,” Petersen replied he couldn't give a “good definition” in the moment. He flubbed Daubert standard, too.

A video of the exchange garnered more than three million views by Friday.

The exchange provided fodder for Democrats and liberal advocacy groups who argue the Trump administration is not thoroughly vetting judicial nominees, who are appointed to lifetime positions and, at the district court level, are key gatekeepers in trials.

Petersen said during the hearing that his background is not in litigation, and that he understood the senator's concerns about his knowledge of trial procedure. So what is Petersen's background? Here are five things to know about the nominee for the U.S. District Court for the District of Columbia:

UVA Grad: He may have had trouble with the law school-like questioning at his hearing, but Petersen graduated in 1999 from the University of Virginia School of Law, routinely ranked one of the best law schools in the country. He was also an editorial board member on the Virginia Law Review, according to his Senate questionnaire. Petersen noted in the questionnaire that he did not clerk for any judge following graduation.

Big Law ties, but no courtroom experience: After law school, Petersen dabbled in Big Law. He worked as a summer associate at Wiley Rein, back when it was Wiley Rein & Fielding, and joined the firm as an associate after graduation. He worked in the firm's election law and government ethics practice for roughly three years, until April 2002.

According to the questionnaire, Petersen's “typical clients” were corporations seeking to comply with campaign finance, election, ethics and lobbying laws. He also represented parties facing enforcement proceedings by the Federal Election Commission. Still, Petersen wrote in the questionnaire that his years at Wiley did not involve “in-court litigation” and that his work for the FEC and on the Hill means he has “not had occasion to appear in court.”

FEC commissioner and ties to White House counsel: Petersen has served as a Republican commissioner on the five-member Federal Election Commission since his nomination in 2008, following the failed nomination of Hans von Spakovsky, a Heritage Foundation fellow and now a member of Trump's election integrity commission. Petersen joined the FEC at the same time as Don McGahn, who served on the commission until 2013 and is now White House counsel.

In 2016, Petersen was chairman of the commission, during which time he sought to improve relations between the partisan members. “Whenever compromise on a topic is possible, I want to find it,” he told the Center for Public Integrity in December 2015.

Major cases: As an FEC commissioner, Petersen had a front row seat to some of the most consequential election law cases of the past few years. Though he was not yet on the commission when Citizens United sued the FEC in 2008, he joined only months after. He was a commissioner when the Supreme Court ruled in the case in 2010, striking down prohibitions on corporations making independent expenditures and electioneering communications.

Petersen was also on the board in 2012, when businessman Shaun McCutcheon sued the FEC over aggregate limits on individual contributions to federal candidates during a two-year period. The Supreme Court issued an opinion in the case in 2014, striking down the limits.

Hill experience: Between Wiley Rein, a brief stint with the Republican National Committee and the FEC, Petersen served in various legal positions on Capitol Hill. He was a counsel to the Committee on House Administration, and then a chief counsel for Republicans on the Senate Committee on Rules and Administration.

In his questionnaire, Petersen said that as chief counsel, he was “heavily involved” in developing lobbying and election reform legislation and advised committee members on campaign finance, election and lobbying reform issues.