Former president Donald Trump is trying to do something that is without modern precedent: use executive privilege, even though he’s no longer president, to stop Congress from investigating his role in fomenting the violence of Jan. 6.

So, far, he hasn’t had any luck.

President Biden ultimately gets to decide that, and the White House has said it will cooperate with the investigators. A federal court agreed that Congress has a right to see hundreds of documents, though the legal battle is expected to continue.

But at the very least, Trump could prevent the committee from getting what it wants just by putting up a lengthy fight that could test the limits of current presidential power vs. a former president’s rights. Here’s how.

First, what is executive privilege?

It’s a loose legal protection for the president and top White House aides designed to give them confidentiality as they make tough decisions while governing, without fearing that those private conversations will be scrutinized by Congress.

Modern presidents have leaned heavily on executive privilege when the White House didn’t want to give information to Congress, but Trump took it to a new level. During his first impeachment, he blocked or tried to block every single records request and subpoena by citing executive privilege.

How is Trump trying to use it against Jan. 6 committee requests?

Two ways: by fighting the release of documents from his time in the White House and by urging his former top aides not to talk to Congress. He’s having more success with the latter.

The special House committee investigating the Jan. 6 insurrection has requested hundreds of pages of documents from federal agencies such as the National Archives and the FBI about the view from the White House and the actions of Republican members of Congress on that day.

Committee members have said they want to know every word that Trump said, even in private, on and leading up to that day.

The committee’s records requests indicate that it is also looking into Trump’s broader efforts to fight his election loss and replace top government officials with his own loyalists. It has subpoenaed 20 Trump aides and advisers, including Mark Meadows, Trump’s chief of staff at the time, and Stephen K. Bannon, a close adviser.

Trump’s lawyer has told those officials not to cooperate, and Bannon and former Justice Department official Jeffrey Clark have either not participated nor fully answered questions for the committee.

And Trump has asserted executive privilege over many of the records the committee wants, telling the government not to release them to Congress because they “contain information subject to executive privilege, including the presidential communications and deliberative process privileges.” His right to do so is based on a law, the Presidential Records Act, that allows him to evaluate that material and say whether he thinks it is privileged information.

The Biden administration has a say in this

Ultimately, it’s not up to Trump whether he gets to claim executive privilege for information within the federal government. It’s up to the Biden administration, since President Biden is the one in charge of the federal agencies that have the records.

And Biden has approved the release of Trump’s information over the former president’s objections. “The president’s dedicated to ensuring that something like that could never happen again, which is why the administration is cooperating with ongoing investigations,” White House press secretary Jen Psaki said.

Trump’s next step was to sue the administration, Congress or both to try to stop the release, claiming that Biden is handing over records that he deems private. On Tuesday, he lost that suit. A federal court agreed with the committee that it has a legitimate legal interest in understanding in great detail what happened that day and Trump’s role in it. Trump is expected to appeal, and the case could go all the way to the Supreme Court.

We don’t have a good sense of what the justices will decide.

There isn’t much precedent for whether a sitting president can and should protect a former president, said Josh Chafetz, a law professor at Georgetown University who wrote a book about the separation of powers. Harry S. Truman tried once to ignore a congressional committee subpoena that came after he had left the presidency. That created such a political firestorm that Congress backed down before the question of former presidents and executive privilege could be settled in the courts.

There could be more lawsuits

The Jan. 6 committee could sue Trump right back to assert that he doesn’t have privilege over the documents it wants, though so far it hasn’t taken steps to do so.

Congress has successfully sued Trump before to get his tax records. But it took awhile. The case went all the way to the Supreme Court and back down, and only recently did a judge rule that lawmakers can have some — but not all — of the records they requested years ago.

People involved in the investigation point out that there’s a long history of the White House handing over sensitive communications to Congress when it is in the greater public interest, and they argue that the origins of the Jan. 6 insurrection certainly fit that mold.

President Gerald Ford testified about his pardon of former president Richard M. Nixon. President Bill Clinton made two senior White House officials available to Congress for an entire day of testimony during his impeachment trial.

Whether Trump can win a legal battle may be a moot point. He can drag things out for a few years knowing it’s possible that Republicans will take control of the House in January 2023 and that they’ll decide to drop the investigation. The top House Republican, Kevin McCarthy (Calif.), adamantly opposes this special committee.

“And that ends the whole thing,” Chafetz said.

Or Congress could get creative

The committee could negotiate. It doesn’t have a lot of time to get tied up in court, so it could allow Trump to keep something private in exchange for another records request.

Former aides the committee is targeting are in a similarly tough situation as Trump. They could try to fight the subpoenas by arguing that they are politically motivated, but “no court has recognized that as a reason in itself,” said Stanley Brand, a congressional ethics expert. Bannon in particular is trying to cite executive privilege, even though he didn’t work in the White House during the time the committee wants to learn more about. Congress ended up citing Bannon for contempt and asking the Justice Department to consider criminal charges against him.

The committee can also go around these people by going to the private sector for information.

Lawmakers are looking at social media posts related to Trump and call logs from key people on that day. They’ve asked Google, Facebook and Twitter to hand over information related to misinformation campaigns at that time; many social media companies indicate they’re complying with the requests.

The committee may also try to capture phone records from people such as members of Congress. McCarthy has threatened telecommunication companies against complying, but his threat wasn’t rooted in any federal law that legal experts are aware of.

Finally, Congress does have the authority to jail people who don’t comply with its subpoena requests. But it’s a dormant power that Democrats haven’t been willing to exercise in the recent past when Trump officials ignored their subpoenas.

But at least two lawmakers on the committee is starting to talk about that — as well as about charging people with a crime — as an option. (Jailing people is known in Congress-speak as “inherent contempt power”).

“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 B. Raskin (D-Md.). “And that means criminal contempt citations, civil contempt citations and the use of Congress’s own inherent contempt powers.”

“If witnesses do not show up, we will hold them in criminal contempt,” said Rep. Adam Schiff (D-Calif.), “we will vote them in contempt in the House, and we will refer them for prosecution.”

This article has been updated with the latest news.