To call Corey Lewandowski’s appearance before the House Judiciary Committee on Tuesday problematic would be generous. It was a strutting spectacle of contempt for democratic processes worthy of President Trump himself. Mr. Lewandowski’s performance requires a serious response. Maybe more than one.

The inaugural witness in this phase of the Democrats’ impeachment inquiry, Mr. Lewandowski had no interest in shedding light on any of the troubling episodes cited in the Mueller report. Instead, he worked to make a mockery of the proceedings, prove his devotion to the president and gin up attention for a possible Senate run, which he teased on Twitter at one point.

He refused to answer lawmakers’ questions, claiming some nebulous version of executive privilege that almost certainly does not cover his conversations with the president. The White House had provided a note excusing him from talking about much of anything, which he repeatedly read aloud. He boasted of his dishonesty and went all in on the partisan trolling. He even worked a swing at Hillary Clinton into his opening remarks. “Such a beautiful Opening Statement! Thank you Corey!” Mr. Trump tweeted from Air Force One.

Give Mr. Lewandowski points for knowing his audience.

While The Lewandowski Show was striking in its awfulness, it also suffered from more mundane problems common to such hearings. These high-profile televised events bring out the worst in lawmakers, who cannot resist the opportunity to preen and try to score political points. Extracting useful information from witnesses can seem like an afterthought.