Mr. Jones asked if the senator would have him arrested.

“You’re not going to get arrested,” Mr. Rubio continued. “I’ll take care of you myself.”

“Oh, he’ll beat me up. He doesn’t know who I am, but he is so mad,” Mr. Jones said with excitement. “You are not going to silence me. You are not going to silence America. You are literally like a little gangster thug. Rubio just threatened to silence me.”

The senator walked away and the show went on.

For Mr. Jones, the appearance of top Facebook and Twitter executives was personal enough to bring his trolling out of the dark corners of the internet and into the halls of the House and Senate.

In early August, Facebook and YouTube banned Mr. Jones and Infowars from their platforms, drastically reducing his reach. Since then, he has led an on-air crusade against the companies, pointedly accusing them of an unfounded campaign to suppress conservative speech.

“I am here to face my accusers one way or another,” he declared to a bank of cameras just outside a hearing of the Senate Intelligence Committee, where Sheryl Sandberg, Facebook’s chief operating officer, and Jack Dorsey, the chief executive of Twitter, faced questions from senators about how to combat foreign influence campaigns on their platforms. He urged lawmakers either to block the companies from banning users or to simply break the companies up.

“The real election meddling is by Facebook and Google and others that are shadow banning people,” Mr. Jones bellowed. “They are outright banning people and they are blocking conservatives involved in their own First Amendment political speech.”

Neither Mr. Jones nor Infowars actually earned a mention inside the Senate’s hearing room, as lawmakers debated how to combat the ability of foreign powers like Russia to influence the American political process. But later in the day, as House Republicans on the Energy and Commerce Committee pressed Mr. Dorsey on what they called Twitter’s censorship of conservative political figures and viewpoints, Mr. Jones’s arguments appeared to have more resonance.