With a defiant flurry of speechifying, Stephen K. Bannon, a longtime ally of former President Donald J. Trump, reported to prison on Monday to begin a four-month sentence for contempt of Congress, days after the Supreme Court rejected his last-ditch effort to avoid incarceration.
Mr. Bannon arrived outside the federal lockup in Danbury, Conn. — a low-security facility about 60 miles north of Manhattan — before noon, and used his last moments of freedom to host a loud rally and live-streamed news conference, surrounded by supporters waving flags and ringing cowbells.
Standing alongside Representative Majorie Taylor Greene, the far-right congresswoman from Georgia, and Bernard B. Kerik, the former New York police commissioner who spent three years imprisoned on fraud charges, Mr. Bannon predicted big victories for Republicans in this year’s election. He slammed what he called “the ruling elite” in America.
“Victory or death,” Mr. Bannon said, just before being blessed by a priest. “We either win or we’re going to have the death of a constitutional republic.”
The circuslike atmosphere is likely to stand in stark contrast to life behind bars, where Mr. Bannon, 70, will spend the most of the remaining time in this year’s election cycle. A brash and influential figure in right-wing circles, Mr. Bannon was found guilty in 2022 of defying a subpoena from the House committee investigating the Jan. 6, 2021, attack on the Capitol.
Mr. Bannon is one of several figures close to Trump who have had legal problems, including the former president himself, who was convicted on 34 felony charges in state court in New York in late May. Those charges — falsifying business records to cover up a $130,000 hush-money payment to the porn star Stormy Daniels — also carry the possibility of prison time, or lesser punishments like probation. Mr. Trump, 78, will be sentenced on July 11.
Before Mr. Bannon arrived on Monday, Ms. Greene spoke outside the prison, saying that Mr. Bannon’s opinions would not be suppressed.
“This is going to multiply Steve Bannon’s voice by ten thousand,” she said on Real America’s Voice, a conservative network, before criticizing the Justice Department and Attorney General Merrick B. Garland.
Elsewhere, pro-Biden and pro-Trump demonstrators traded remarks and insults, with one supporter of the former president holding a poster that said “free Biden’s political prisoners.”
The House committee had sought to question Mr. Bannon about efforts before the Jan. 6 riot at the Capitol to coordinate with Republican members of Congress to challenge the results of the 2020 election. Members also wanted to question him about remarks he had made on his podcast, “War Room,” the day before, warning that “all hell was going to break loose” the following day.
Another Trump aide, Peter Navarro, also defied a subpoena from the Jan. 6 committee, and is serving a four-month prison term in Florida.
Mr. Bannon also faces a trial in Manhattan — scheduled to begin later this year — in which he stands accused by the state of misusing money he had helped raise for a group backing the former president’s attempt to build a wall on the southern border. That case will take place in the same courthouse where Mr. Trump was convicted in May.
After speaking on Monday, Mr. Bannon was driven into the prison in a black Cadillac Escalade, pausing briefly at the entrance where two guards stood. In his remarks before beginning his time behind bars, he had told supporters that he was “prepared to do this mentally” and physically, casting his legal travails as a minor setback in the face of a rising right-wing tide in the United States and abroad.
“We’re winning everywhere,” he said. “And we’re going to win more. This has just started.”