Former Defense Secretary Mark Esper filed a lawsuit Sunday against the Defense Department, accusing the Pentagon of "censoring" his First Amendment rights by redacting aspects of his upcoming book on the Trump administration.

The big picture: Esper, who served as defense secretary from July 2019 until he was fired by then-President Trump in November last year, alleges in the suit that "significant text" is "being improperly withheld from publication" of the manuscript "under the guise of classification."

• "The withheld text is crucial to telling important stories discussed in the manuscript," adds the suit, filed in federal court in Washington, D.C., and first reported by the New York Times.
• The suit alleges that Esper raised concerns with current Defense Secretary Lloyd Austin, writing in a Nov. 8 email that "some requested redactions asked me to not quote former President Trump and others in meetings, to not describe conversations between the former president and me, and to not use certain verbs or nouns when describing historical events."

What they're saying: Esper said in a statement that his memoir, "A Sacred Oath," due to be released in May, "offers important details and new insights into many of the most controversial events that occurred during the tumultuous second half of the Trump Administration."

The other side: Pentagon spokesperson John Kirby said in an emailed statement that he's "aware" of "Esper's concerns regarding the pre-publication of his memoir."

• "As with all such reviews, the department takes seriously its obligation to balance national security with an author’s narrative desire," Kirby added.
• "Given that this matter is now under litigation, we will refrain from commenting further."

What to watch: Esper has asked the D.C. District Court to permit the publication of unclassified information in the book.

Editor's note: This article has been updated with further details of the case.