The special House committee investigating the Jan. 6 insurrection is taking an aggressive step to get former Trump aides to talk to them. After former adviser Stephen K. Bannon refused to comply with a subpoena this week, the committee said they’ll start the process of prosecuting him, which could even end with Bannon in jail.

It’s a warning to others who might avoid talking. The committee has also asked former White House chief of staff Mark Meadows, former deputy chief of staff Dan Scavino, former Pentagon official Kash Patel and Bannon, as well as former top Justice Department official Jeffrey Clark to testify or provide documents. Trump’s lawyer has told them not to cooperate, as Trump himself fights the release of documents from the White House about his conversations surrounding the insurrection and attempts to overthrow the 2020 election.

So what can lawmakers do to enforce the subpoenas or punish the holdouts? Congress has a few options. The toughest one is potentially jailing the holdouts such as Bannon, something they are now actively moving to do.

“Mr. Bannon has declined to cooperate with the Select Committee and is instead hiding behind the former President’s insufficient, blanket, and vague statements regarding privileges he has purported to invoke. We reject his position entirely,” Chairman Bennie G. Thompson (D-Miss.) said in a statement Thursday. “The Select Committee will not tolerate defiance of our subpoenas, so we must move forward with proceedings to refer Mr. Bannon for criminal contempt.”

Here’s what that means and how it could escalate into jail time for Bannon and others.

First, they vote to hold someone who doesn’t comply in contempt of Congress.

While that sounds intense, it’s a threat that’s been watered down as it happens with increasing frequency. Attorneys general of the past two White Houses have been held in contempt of Congress by Houses controlled by the opposite party, and nothing happened to them. A contempt vote is fast becoming the equivalent of a slap on the wrist.

Congress often stops there, but they don’t have to.

Lawmakers can take that contempt citation and hand it over to the Justice Department and ask the government to prosecute the person ignoring the subpoena. That’s what Thompson said they’ll do with Bannon.

Worst-case scenario, Bannon could be charged with a crime and face jail time.

Congress can sue the person and demand they comply

The courts have long upheld Congress’s right to use this power, though Trump fought the Democratic House’s various investigations into him every step of the way. House Democrats spent two years tied up in court trying to get former White House counsel Donald McGahn to testify about the Russia investigation; he eventually did this summer.

Most recently, a case from Congress to get Trump’s tax records went all the way to the Supreme Court and back down. A judge ruled that lawmakers can have some — but not all — of the records. Congress got those tax records years after they initially requested them.

Or they could jail them in the halls of Congress

Yes, Congress can send out its sergeant-at-arms to arrest people who ignore its subpoenas. It’s a dormant power that Democrats briefly talked about using in the Trump era when they held Attorney General William P. Barr in contempt.

But Congress doesn’t have a jail. A century or so ago, they held people in empty committee rooms for a few days, or they asked the D.C. jail to hold them.

As dramatic as this sounds, this fourth option is something lawmakers on the Jan. 6 committee are at least talking about. “This is a matter of the utmost seriousness, and we need to consider the full panoply of enforcement sanctions available to us,” said Rep. Jamie Raskin (D-Md.). “And that means criminal contempt citations, civil contempt citations and the use of Congress’s own inherent contempt powers.” (“Inherent contempt power” is Congress-speak for jailing people.)

Congress’s enforcement power has some weak points. If someone really wants to flout a subpoena, lawmakers have to be willing to get really aggressive — such as potentially arresting them — to bring them before their committee. Or Congress has to wrangle the person in court for months or years.

How Trump aides can try to defend themselves

There are a few legal exceptions to complying with a subpoena, most notably claiming executive privilege — a loose protection for the president and top White House aides as they make tough decisions while governing, without fearing that those private conversations will be scrutinized by Congress.

Trump isn’t president anymore, but he’s trying to claim executive privilege to stop the committee from getting more information about his internal conversations around Jan. 6. He isn’t actually receiving any subpoenas, but the committee has asked the National Archives to hand over Trump’s records. President Biden has agreed to release the records. Trump can try to stop that by going to court, where he has a good chance to at least delay the records requests.

Bannon is trying to cite executive privilege, even though he didn’t work in the White House at the time the committee is concerned with investigating. Other former Trump aides and advisers could follow.

People on the receiving end of these subpoenas — including any members of Congress that the committee might try to talk to — could try to fight them, arguing that the subpoenas are politically motivated.

But “no court has recognized that as a reason in itself,” said Stanley Brand, a congressional ethics expert. And Republicans as well as Democrats have signed off on these subpoenas. Plus, a majority of Republican lawmakers opposed an investigation into the attack on the U.S. Capitol, but two Republicans — Liz Cheney of Wyoming and Adam Kinzinger of Illinois — agreed to serve on it.

So while Congress’s enforcement power of subpoenas has its weak spots, if it wants to really ramp up the pressure, there aren’t a lot of ways around avoiding a subpoena, other than going to jail.