President Trump is seen as he delivers a message during the daily briefing hosted by U.S. White House Press Secretary Sarah Huckabee Sanders at the White House in Washington. (Carlos Barria/Reuters)

A host of legal issues complicate President Trump's effort to block publication of a book highly critical of his tenure in the White House, according to legal experts who view it more as an attempt at intimidation than a genuine threat of litigation.

"It is unthinkably difficult to imagine a president suppressing publication of a book criticizing him," said Floyd Abrams, a noted First Amendment lawyer who has represented the media. Journalism evaluating the president's performance in office receives "the super-highest levels of First Amendment protection."

Trump lawyer Charles J. Harder of Beverly Hills, Calif., sent an 11-page letter Wednesday night to the publisher of author Michael Wolff's new book "Fire and Fury: Inside the Trump White House," saying it included false and libelous statements that could result in "substantial monetary dam­ages and punitive damages."

"Mr. Trump hereby demands that you immediately cease and desist from any further publication, release or dissemination of the book, the article, or any excerpts or summaries of either of them, to any person or entity, and that you issue a full and complete retraction and apology to my client as to all statements made about him in the book and article that lack competent evidentiary support," the letter said.

The letter was sent to Wolff and Steve Rubin, president and publisher of Henry Holt & Co. The company issued a statement Thursday confirming that it had received the letter and would proceed with publication: "We see 'Fire and Fury' as an extraordinary contribution to our national discourse."

The book, which has been excerpted in a magazine since Wednesday, was originally scheduled for release next week, but Wolff and the publisher announced Thursday that the release had been moved up to Friday. Various news organizations have obtained copies, including The Washington Post, which said it depicted Trump as "presiding over a chaotic White House, struggling to settle into his new reality and eagerly trying to maintain his normal golf habits."

Harder is an experienced libel lawyer who has represented Melania Trump and, briefly, Hollywood producer Harvey Weinstein, among others. In a lawsuit funded by technology entrepreneur Peter Thiel, he successfully represented wrestler Hulk Hogan in an ­invasion-of-privacy case against Gawker Media, which resulted in the closing of the website.

Some people have disputed Wolff's descriptions of scenes in which they are mentioned in the book, and the White House has unleashed an escalating string of insults to denounce Wolff and his reporting.

It is exceedingly difficult for any public official to prove libel. It requires a plaintiff to show that a writer knew the disputed statement was false but printed it anyway or acted with "reckless disregard." That requires proof that the writer seriously doubted the truth of what he wrote.

"The demand for proof of reckless disregard is at its zenith when it comes to the president and the White House," said Ronald K.L. Collins, a First Amendment scholar at the University of Washington School of Law.

Collins said the demand that Holt cease publication of the book, which appears to be on its way to the bestseller list, did not seem serious. "The cinematic world has come to the real world," he said.

He was referring to the current movie "The Post," which concerns attempts to halt the New York Times and The Washington Post from publishing the Pentagon Papers, a history of the U.S. government's efforts in Vietnam.

The difference there, of course, was that it was the government trying to stop publication; the Supreme Court eventually ruled that the papers were free to publish their reports.

Here, it is a private lawyer trying to convince a company not to publish a book, albeit one about the president.

Sonja R. West, a First Amendment expert at the University of Georgia School of Law, said that while the Supreme Court has not ruled prior restraint unconstitutional, it has noted that it is "the most serious and least tolerable restraint on the First Amendment."

Rare cases of blocking publication usually involve issues such trade secrets or concerns about privacy, such as a person's medical condition.

In cases concerning libel and defamation, it is up to the publication to decide whether to publish, and the offended subject can then sue for damages.

Collins wondered what those damages would be in Trump's case.

"This is a president who revels in bad press," he said. "In a sense, bad press is his best publicity."

West expressed concern about the most powerful politician in the world threatening the publication of a book that criticized his performance, rather than simply defending himself against the depiction.

"It is yet another norm he seems to be violating," she said. "Really, it goes against the underlying basic principles of the First Amendment."