TEMPERS BOILED over on Capitol Hill Thursday as Peter Strzok, the FBI official at the center of President Trump’s attempts to discredit special counsel Robert S. Mueller III, testified before a joint meeting of two House oversight committees. With all its yelling and interruptions, the hearing was a fitting coda to the hyperpartisan farce of an investigation that House Republicans have conducted into the FBI and Mr. Mueller’s Russia probe.

Republicans spent hours parsing text messages and waving documents in the air. But all of it, just like most of the broader House investigation, was a distraction from this central point about the conspiracy narratives the president and his defenders have been cooking up about the FBI: If the agency had been trying to harm Mr. Trump’s campaign, agents could have released damaging information on pro-Trump Russian interference before Election Day — and they did not.

The investigators certainly had a lot they could have spilled. “In the summer of 2016, I was one of a handful of people who knew the details of Russian election interference and its possible connections with members of the Trump campaign,” Mr. Strzok said. “This information had the potential to derail, and quite possibly, defeat Mr. Trump. But the thought of exposing that information never crossed my mind.”