WASHINGTON — The House voted Thursday to hold Steve Bannon, a longtime ally and aide to former President Donald Trump, in contempt of Congress for defying a subpoena from the committee investigating the Jan. 6 Capitol insurrection.

The committee’s Democratic chairman, Mississippi Rep. Bennie Thompson, led the floor debate along with Republican Rep. Liz Cheney of Wyoming, one of two Republicans on the panel. The vote was 229-202.

The House vote sends the matter to the U.S. attorney’s office in Washington, where it will now be up to prosecutors in that office to decide whether to present the case to a grand jury for possible criminal charges. It’s still uncertain whether they will pursue the case.

The partisan split over Bannon’s subpoena — and over the committee’s investigation in general — is emblematic of the raw tensions that still grip Congress nine months after the Capitol attack. Democrats have vowed to comprehensively probe the assault in which hundreds of Trump’s supporters battered their way past police, injured dozens of officers and interrupted the electoral count certifying President Joe Biden’s victory.

Lawmakers on the investigating committee say they will move swiftly and forcefully to punish anyone who won’t cooperate with the probe.

“We will not allow anyone to derail our work, because our work is too important,” Thompson said ahead of the vote.

Republicans call it a “witch hunt,” say it is a waste of time and argue that Congress should be focusing on more important matters than the insurrection.

Indiana Rep. Jim Banks, leading the GOP opposition on the floor, called the probe an “illicit criminal investigation into American citizens” and said Bannon is a “Democrat party boogeyman.”

Cheney and Illinois Rep. Adam Kinzinger are the only two Republicans on the Jan. 6 panel, and both have openly criticized Trump and his role in fomenting the insurrection.

The Jan. 6 committee voted 9-0 Tuesday to recommend the contempt charges after Bannon missed a scheduled interview with the panel last week.

Lawmakers on the panel said Bannon was alone in completely defying its subpoena, while more than a dozen other subpoenaed witnesses were at least negotiating with them.

Even if the Justice Department does decide to prosecute, the case could take years to play out.

There’s still considerable uncertainty about whether the department will pursue the charges.

Democrats are pressuring Justice to take the case, arguing that nothing less than democracy is on the line.

“The stakes are enormous,” Maryland Rep. Jamie Raskin said in an interview with The Associated Press.

If the Justice Department doesn’t prosecute, the House has other options, including a civil lawsuit. That could also take years but would force Bannon and any other witnesses to defend themselves in court.

Another option would be for Congress to try to imprison defiant witnesses — an unlikely, if not outlandish, scenario. Called “inherent contempt,” the process was used in the country’s early years but hasn’t been employed in almost a century.

The lingering acrimony over the insurrection, and the Bannon subpoena, was evident Wednesday at a House Rules Committee hearing held to set the parameters of Thursday’s debate.