The dramatically escalating feud between President Trump and his former adviser Steve Bannon reached a new zenith Wednesday night when Trump’s lawyer hit Bannon (and author Michael Wolff) with a cease and desist letter.

But the letter, which argues that Bannon violated a confidentiality agreement when he made disparaging comments about the Trump Administration in a new book, raises more questions than answers.

Here’s everything you need to know about the letter and the potential legal issues between Trump and Bannon.

What does the letter say?

Trump’s personal attorney Charles J. Harder of the firm Harder Mirell & Abrams LLP sent the cease and desist letter Wednesday night after excerpts from Wolff’s book Fire and Fury: Inside the Trump White House surfaced, in which Bannon made derisive comments about Trump’s cognitive abilities and alleged that Donald Trump Jr. set up a Trump Tower meeting with a Russian attorney, which Bannon calls “treasonous.”

“You [Bannon] have breached the Agreement by, among other things, communicating with author Michael Wolff about Mr. Trump, his family members, and the Company, disclosing Confidential Information to Mr. Wolff, and making disparaging statements and in some cases outright defamatory statements to Mr. Wolff about Mr. Trump, his family members, and the Company, knowing that they would be included in Mr. Wolff’s book and publicity surrounding the marketing and sale of his book,” Harder’s letter says, ABC News reports.

Confidential information, the letter says, includes “all information . . . of a private, proprietary or confidential nature or that Mr. Trump insists remain private or confidential, including, but not limited to, any information with respect to the personal life, political affairs, and/or business affairs of Mr. Trump or of any Family Member.”

Is a cease and desist letter legally binding?

No. Cease and desist letters caution the recipient that they could be sued if they continue their behavior, but the letter is a formal warning, not the beginning of a lawsuit.

Could Trump bring a defamation suit?

The letter says so, arguing Bannon made “outright defamatory statements” about Trump to the book’s author. But defamation cases are notoriously hard to prosecute. In the 1964 Supreme Court Case New York Times v. Sullivan, the court ruled that the publication of false statements about public officials (and Trump certainly qualifies as a public official) is protected by the First Amendment unless the statements are made with “actual malice.” In other words, Trump’s legal team would have to prove not only that Bannon’s statements about Trump were wrong, but also that Bannon knew they were wrong or acted with reckless disregard to whether they were true. That’s a very high legal standard to meet. Bannon may be wrong that the Trump Tower meeting was “treasonous,” but if that’s him expressing his opinion, that’s not defamation.

Asked in the daily press briefing Thursday about the high bar for defamation suits, White House spokeswoman Sarah Sanders declined to comment on legal matters but said, “In terms of the merits, I think it’s pretty clear. … It’s completely tabloid gossip, full of false and fraudulent claims.”

Did Bannon violate a non-disclosure agreement?

It has been widely reported that Trump used to make Trump Organization employees and members of his campaign sign broad non-disclosure agreements to work for him. One campaign confidentiality agreement was made public in 2016, and it said, in part, that the employee could not publicly “demean or disparage … the Company, Mr. Trump, any Trump Company, any Family Member, or Any Family Member Company.”

The terms of any agreement Bannon may have signed during his time working for Trump have not been revealed. But the language of the cease and desist letter, which specifically mentions Bannon breaching his agreement by talking to Wolff “about Mr. Trump, his family members, and the Company,” suggests the language of his agreement may have been similar to the 2016 campaign document.

Trump has issued this letter saying Bannon violated his agreement and “disclos[ed] Confidential Information” to Wolff, but Trump and his representatives are also arguing that the book is largely false. Sanders said Wednesday that many assertions in the book are “completely untrue,” and Trump said in a statement that Bannon “was rarely in a one-on-one meeting with me and only pretends to have had influence to fool a few people with no access and no clue, whom he helped write phony books.”

Did the legal situation change when Trump became president?

Yes. We know Trump made employees of his business, campaign, and even transition team sign non-disclosure agreements. And he told the Washington Post during his campaign that he would support having the agreements for White House staff too. “I think they should,” he said in April 2016. “When people are chosen by a man to go into government at high levels and then they leave government and they write a book about a man and say a lot of things that were really guarded and personal, I don’t like that. I mean, I’ll be honest. And people would say, oh, that’s terrible, you’re taking away his right to free speech. … I would say … I do have nondisclosure deals … But I will say that in the federal government it’s a different thing. So it’s something I would think about.”

But much of Bannon’s speech as a former government employee is protected under the First Amendment, and the only speech restriction on former federal employees concerns disclosing classified information, explains Bradley Moss, a national security and federal employment lawyer at the law office of Mark S. Zaid. “Any of the information that Bannon gave to Wolff and is coming out in this book that was given at the time of his service in the federal government that concerns things that happened during the Administration, as opposed to what happened during the campaign, the campaign NDA is irrelevant,” Moss says. “The only thing that matters is the U.S. government NDA, and that only concerns classified information.”

Asked Thursday whether he made White House staff sign non-disclosure agreements, Sanders said there was an “ethics agreement” in place but wouldn’t comment on any additional details.

“The president absolutely believes in the First Amendment,” Sanders continued. “But … the president also believes in making sure that information is accurate before pushing it out as fact, when it certainly and clearly is not.”

Other experts also scratched their heads at the prospect of any sort of non-traditional federal confidentiality agreement. “I’m confused by talk of WH nondisclosure agreements,” tweeted Walter Shaub, former head of the Office of Government Ethics. “Aside from classified info, I haven’t heard of anything like that in govt. It’s contrary to transparency, 1A, Congressional oversight, whistleblowing, investigations/audits, etc.”

Moss said there likely isn’t any agreement in place between Trump and White House staff beyond what is customary in the federal government.

“That was the president, who had never experienced anything in the federal government in terms of employment, had no understanding of the case law, just mouthing off on something he personally was used to, but didn’t really understand,” Moss said of Trump telling the Washington Post that he might support federal NDAs.

Would Trump actually sue Bannon or Wolff?

Legal experts think probably not. If Trump brought a lawsuit, he would open himself up to the discovery process in a case, which could involve providing documents and depositions.

“This is a public relations stunt, pure and simple, nothing more,” says Moss. “I would put good money on it that there would never be a lawsuit filed. … No one in the White House is going to let him start litigation that’s going to subject him to discovery.”

The White House argues that even if Trump doesn’t pursue legal action, some of his point has already been made by publicly disputing aspects of the book. “Regardless of whether or not there’s a lawsuit,” Sanders said Thursday, “[Bannon and Wolff] should be concerned about peddling fake stories, they should be concerned about putting out information that’s not true, they should be concerned about the fact that we’re spending all of our time here focused on talking about this instead of things that people in this country care about.”

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Write to Tessa Berenson at tessa.berenson@time.com.