The House’s Jan. 6 committee is set Tuesday to recommend criminal contempt charges against former Trump administration staffer Stephen K. Bannon. Mr. Bannon has cast his defiance of a committee subpoena as a matter of principle, declaring through his attorney that he would “honor” former president Donald Trump’s invocation of executive privilege and refuse to turn over documents or sit for a deposition. In fact, this episode is just another chapter in his long career as a far-right provocateur and opportunist, which — astonishingly, given his record — still seems to have life.

This is not the first time that Mr. Trump has shielded Mr. Bannon from official scrutiny. Before Mr. Bannon was flouting the Jan. 6 committee, he was facing federal charges for a massive fraud he allegedly perpetrated on credulous Trump supporters. Prosecutors accused Mr. Bannon of siphoning money from the “We Build the Wall” campaign, a crowdfunding initiative that raised more than $25 million, supposedly to construct a U.S.-Mexico border wall with private funds. The campaign allegedly spent less than half the money it raised on a small amount of wall construction, while Mr. Bannon and his partners allegedly took hundreds of thousands of dollars for themselves.

Mr. Bannon pleaded not guilty, but Mr. Trump pardoned him before his case went to trial. This was an outrageous abuse of presidential pardon authority to help one of the president’s longtime supporters and a sign of the contempt Mr. Trump holds for the ordinary people he has manipulated into trusting him.

Mr. Bannon has cut a mucky path unlike anyone in memory. It was incredible that the man who ran Breitbart, a far-right nationalist cesspool, was ever allowed into the White House, and as a senior adviser to Mr. Trump, no less. It was curious how he managed to keep in Mr. Trump’s good graces even after the former president fired him. It was outlandish that Mr. Trump pardoned him. Now, Mr. Bannon has rehabilitated himself to the point where Republicans such as House Republican Conference Chair Elise Stefanik (R-N.Y.) flock to his show, and he is drawing crowds in Virginia as he rallies support for GOP gubernatorial candidate Glenn Youngkin.

Mr. Bannon may or may not have information relevant to the Jan. 6 committee’s work. He was in touch with Mr. Trump leading up to the desecration of the Capitol. According to the committee, he also participated in a meeting the night before the attack “as part of an effort to persuade Members of Congress to block the certification of the election the next day.” If the House sends the Justice Department a criminal referral, federal authorities should look seriously at prosecuting Mr. Bannon. Congress must have the ability to investigate, a principle that Mr. Trump and his allies have eroded as they routinely defy congressional subpoenas. And Mr. Bannon should not be allowed once again to writhe out of having to face the justice system.