During his confirmation hearing, Attorney General Jeff Sessions testified, under oath, that “I did not have communications with the Russians.” We now know, thanks to the Washington Post, that this is false: Sessions met with the Russian ambassador to the US twice in the past year, when he was serving as both a Trump adviser and a US senator.

The million-dollar questions: Did Sessions break the law? And, if so, could he lose his job — or even be charged with perjury like someone who lied in court? To find out, we reached out to several legal experts who study relevant topics. The general sense was that if Sessions didn’t commit outright perjury, he came uncomfortably close.

“I think a jury presented with evidence that he did have meetings with the Russians during the relevant time period could conclude that he perjured himself in front of the Senate committee,” Stuart Green, a law professor at Rutgers who studies the law of lying, wrote via email.

It’s very unlikely that Sessions will be prosecuted under laws criminalizing perjury, owing both to laws protecting sitting Congress members (which he was at the time of testimony) and due to the difficulty of proving a lie. But there already have been consequences for him: on Thursday afternoon, Sessions announced that he would be recusing himself from any future investigations into the Trump campaign and Russia. That might just be the beginning: a special prosecutor could be appointed, or, even worse, the Senate could begin something called “contempt of Congress” proceedings.

And the consequences could extend beyond Sessions — potentially landing any Trump administration officials who helped him prepare his testimony in legal trouble.

There is a very strong chance Sessions committed perjury

Simply making a false statement to Congress isn’t enough to make you guilty of perjury. Under the statute, you have to willfully deceive Congress — to know that what you were saying was untrue, and say it anyway.

If Sessions didn’t cross the perjury line, he definitely walked right up to it

This makes perjury a hard crime to prove. Nonetheless, there is good reason to believe that Sessions committed it. To see why, let’s look at the exchange with Sen. Al Franken during Sessions’s January 10 confirmation hearing that has that landed him in so much hot water:

FRANKEN: If there is any evidence that anyone affiliated with the Trump campaign communicated with the Russian government in the course of this campaign, what will you do? SESSIONS: Sen. Franken, I am not aware of any of those activities. I have been called a surrogate at a time or two in that campaign, and I did not have communications with the Russians, and I am unable to comment on it.

This seems to be clearly false. Sessions met with the Russian ambassador during the campaign — twice, according to the Post story. This is not normal Senate activity, even for members like Sessions who were on the Armed Services Committee. The Post contacted every current member of the committee and asked them whether they had met with Kislyak last year. All 20 senators they heard from said no.

So it’s unlikely that Sessions just forgot about these meetings. Indeed, the current line out of the Sessions camp is that he remembered — he just interpreted Franken’s question to be about conversations with the Russians in his capacity as a Trump adviser, which he claims to have never had.

“There was absolutely nothing misleading about his answer,” Sessions spokesperson Sarah Isgur Flores said in a press statement. “He was asked during the hearing about communications between Russia and the Trump campaign — not about meetings he took as a senator and a member of the Armed Services Committee.”

Green, the Rutgers expert, did not find this very persuasive.

“The denial [that Sessions did not have] ‘communications with the Russians’ seems quite categorical,” he explains. “It does not leave a lot of room for him to argue that he had communications with the Russians, just on non-Trump matters.”

Sessions’s follow-up behavior makes this defense even weaker. On January 17, Sessions submitted a response to a written questionnaire presented by Sen. Pat Leahy. Leahy asked Sessions a question about Russia, to which he submitted a very terse response:

LEAHY: Several of the President-elect’s nominees or senior advisers have Russian ties. Have you been in contact with anyone connected to any part of the Russian government about the 2016 election, either before or after election day? SESSIONS: No.

Technically, Sessions didn’t repeat his earlier false statement here — he didn’t deny all contact with Russians, just contact regarding the 2016 election. The problem, though, is that this question gave him an opportunity to clarify his earlier misleading testimony by admitting that he had met Kislyak in his capacity as ambassador — and he didn’t do it.

“Sessions’s failure to clarify his response afterward is also incriminating,” Ryan Goodman, a New York University law professor and the co-editor of Just Security, a national security law publication, says. “Sessions’s failure to clarify his problematic answer in his follow-up responses to Leahy is evidence that his initial comment was willfully misleading the committee.”

Now, none of this proves that Sessions committed perjury. Given the high standard of proof, and how critically it depends on Sessions’s state of mind, it’s an extremely difficult case to make conclusively.

“This is one of those situations when the testimony was highly misleading. Whether or not it amounts to perjury is debatable,” Richard Painter, a University of Minnesota professor who served as President George W. Bush’s chief ethics lawyer from 2005 to 2007, told Vox.

But if Sessions didn’t cross the perjury line, he definitely walked right up to it.

Sessions is very unlikely to be prosecuted

The chances of Sessions being prosecuted are, despite all of this, very slim.

“Almost no one is prosecuted for lying to Congress,” US Attorney for Northern Texas P.J. Meitl wrote in a 2007 law review essay (Meitl was, at the time, in private practice). “In fact, only six people have been convicted of perjury or related charges in relation to Congress in the last sixty years.”

There are a number of reasons for this, according to Meitl: The statutes make perjury very hard to prove, there’s not much political will to prosecute, and Congress members generally aren’t good enough questioners to pin down a witness in a clear lie. These factors may or may not be present in the Sessions case — it’s too soon to say, given that the news just broke — but it suggests the baseline expectation should be that he won’t be prosecuted.

To make matters even more complicated, there are special constitutional protections for sitting members of Congress. Article I, Section 6, Clause 1 of the US Constitution states that “for any Speech or Debate in either House, they [meaning senators and representatives] shall not be questioned in any other Place.” In plain English, this means that Congress members can’t be prosecuted for things they say when they are speaking in Congress.

According to Josh Chafetz, a Cornell University law professor who studies this provision, this should protect Sessions from prosecution over his testimony.

“There is no doubt that Sessions was a senator at the time, there is no doubt that a court counts as ‘any other place,’ and there is no doubt that the protection applies when members are speaking in committee, not just when they’re on the floor,” he says.

Not every expert agrees with Chafetz.

Larry Tribe, a constitutional scholar at Harvard, tweeted that the Constitution only protects speeches given by Congress members — not sworn testimony they give in their capacity as administration nominees. It’s hard to say who’s right, because there’s no actual case law either way. But the fact that prosecuting Sessions is even arguably unconstitutional creates yet another burden for a case that’s already tough to prosecute.

Finally, there’s the question of who would prosecute Sessions. Normally, the US attorney’s office would investigate perjury in Congress, but Sessions is in charge of the US attorneys. Theoretically, that means Sessions’s deputy would be tasked with appointing a special prosecutor — but it’s not actually clear whether acting Attorney General Dana Boente, a Trump appointee, would want to.

In short, then, the deck is stacked against a Sessions prosecution. Don’t expect to see the attorney general in a courtroom anytime soon.

The scandal could still have serious consequences — for both Sessions and the Trump administration

Sessions’s false testimony could nonetheless be a serious problem for him and his boss.

Two key Republicans, Sen. Lindsey Graham and House Oversight Committee Chair Rep. Jason Chaffetz, have called on Sessions to recuse himself from the ongoing FBI investigation into Trump’s Russia ties (technically, Sessions is in charge of the FBI).

Sessions’ recusal may satisfy these Republicans, but Democrats are going further. Both Senate Minority Leader Chuck Schumer and House Minority Leader Nancy Pelosi have called on Sessions to resign.

This kind of congressional uproar creates a major problem for Sessions. According to Cornell’s Chafetz, Congress could punish Sessions on its own even if the courts choose not to — holding what are called “contempt of Congress” proceedings. Theoretically, Congress could even mete out jail time if it wanted to.

Sessions’s former colleagues almost certainly will not imprison him. But a sustained push for a contempt of Congress resolution, if one starts, could very well force him to resign.

“Given that it would require Republican support to pass the contempt resolution, the publicity would be pretty bad indeed,” Chafetz says. “He’d probably already have resigned by that point.”

The key issue now, is how Sessions handles himself — whether he sufficiently appeases his critics on Capitol Hill, particularly fellow Republicans, and heads off this kind of punishing fight. The recusal is a first big step; we’re about to see if it’s enough.

Even if Sessions survives the congressional furor, it’s not obvious that other Trump staffers will. If anyone from the White House helped Sessions prepare his Russia testimony, and told Sessions to say he had no contact with the Russians, then they too would be on the hook.

“Such an individual could be directly implicated under federal criminal law, which makes it illegal to aid, abet, or, in this case, ‘counsel’ the commission of a federal offense,” Goodman says. “Whenever associated individuals are in legal jeopardy, it can assist investigators who can offer them immunity for providing information about the principal crime.”

Sessions’s Senate staff, according to Chafetz, would likely be protected by the Constitution (because they were serving as his “alter ego,” meaning that, legally speaking, his privileges extend to them). The situation is different for White House staffers, because they’re in a different branch of government and not directly employed by Sessions.

“If it were White House staffers who were helping him prepare, I suppose it’s possible they could be charged with conspiracy to commit perjury and/or aiding perjury,” Chafetz says.

So this investigation won’t stop with Sessions. If a reporter or congressional staffer uncovers evidence that a White House aide instructed Sessions to deceive on his meetings with Kislyak, or helped him craft the lie, then that person really could face prosecution.

The investigation into Sessions and his possible perjury is only just beginning. The aftershocks will be felt well into the future.

Tara Golshan contributed reporting to this piece.