A new book by Omarosa Manigault Newman, "Unhinged: An Insider's Account of the Trump White House," is displayed on a shelf at Book Passage in Corte Madera, Calif. (Justin Sullivan/Getty Images)

The publisher of former Trump aide Omarosa Manigault Newman’s explosive new book on Wednesday issued a defiant rebuttal to what it described as “hollow legal threats” from a Trump campaign attorney.

The gist of the message: We will not be silenced.

“Mr. Trump is the President of the United States, with a ‘bully pulpit’ at his disposal,” Simon & Schuster outside counsel Elizabeth McNamara said in the letter, a copy of which was obtained by The Washington Post. “To the extent he disputes any statements in the Book, he has the largest platform in the world to challenge them.”

Simon & Schuster, McNamara added, “will not be intimidated by hollow legal threats and have proceeded with publication of the Book as scheduled.”

The letter was addressed to Trump campaign litigation counsel Charles Harder, who on Monday sent a letter to Simon & Schuster executives threatening that the book’s publication would subject the company to liability for “substantial monetary damages and punitive damages.”

Trump has threatened legal action against book authors and other perceived adversaries in the past but has not followed through on many occasions.

Manigault Newman is in the midst of a media blitz to promote the book, “Unhinged,” which hit bookstore shelves on Tuesday. The tell-all paints Trump as a bigot and questions his mental health; it also details an alleged $15,000-a-month job offer from the Trump campaign to Manigault Newman in an effort to buy her silence after she was fired from her position in the White House last year.

After Manigault Newman had kicked off her media tour and excerpts of the book had been reported by The Post and other news outlets, Harder on Monday argued in his letter to Simon & Schuster executives the book’s publication violated the terms of Manigault Newman’s nondisclosure agreement with the Trump campaign.

Without specifying details, Harder said excerpts of the book “contain confidential information and disparaging statements” and the Trump campaign’s potential claims against the publisher include tortious interference and inducement of Managault Newman to breach her NDA with the campaign.

“Now that you are aware of these contractual provisions, and Ms. Manigault-Newman’s breaches thereof, the Company will have claims against you, and all persons working in concert with you, should you proceed with publishing and selling the Book,” Harder said, according to a copy of the letter obtained by The Post.

The letter from Harder is separate from the arbitration action filed by Trump’s campaign against Managault Newman earlier this week. Manigault Newman, who has also been releasing a steady stream of audio recordings of her conversations with Trump and White House and campaign officials, has said she does not believe she has violated the agreement and contends the Trump campaign is trying to silence her.

In her response to Harder, McNamara said Manigault Newman had shopped her book to several publishers, so it would be difficult to argue she was induced by Simon & Schuster to break the agreement.

“An after-the-fact lawyer’s letter putting my clients ‘on notice’ does not put the proverbial genie back into the bottle, much less subject S & S to liability for Ms. Manigault-Newman’s purported contractual obligations,” she said in the letter.

McNamara noted many of the book’s early excerpts referenced episodes from Manigault Newman’s time in the White House rather than on the campaign. Harder, she added, did not identify any particular excerpts as false, and the Trump campaign “does not have a viable legal claim merely because unspecified truthful statements in the Book may embarrass the President or his associates.”

And in a line that echoes Manigault Newman’s own defense of the book, McNamara said the book was primarily aimed at educating readers about the leader of the country.

“Put simply, the book’s purpose is to inform the public,” she said. “Private contracts like the NDA may not be used to censor former or current government officials from speaking about nonclassified information learned during the course of their public employment.”

Adam Rothberg, Simon & Schuster’s senior vice president for corporate communications, confirmed in a statement Thursday plans for the book’s publication will continue unchanged.

“Despite various legal claims and threats made by representatives of the Trump campaign, Gallery Books and Simon & Schuster are proceeding as planned with publication of UNHINGED by Omarosa Manigault-Newman, confident that we are acting well within our rights and responsibilities as a publisher,” Rothberg said.

John Wagner contributed to this report.