The threat of a mass firing was unspoken but loomed over the videoconference call.

Summoning the staff of the Justice Department’s public integrity section on Friday morning, the acting deputy attorney general, Emil Bove III, was matter-of-fact. Two lawyers needed to step forward to sign a request to dismiss corruption charges against Mayor Eric Adams of New York.

An earlier call with the section’s supervisors had gone badly. Three of them quit rather than abandon an important criminal case for brazenly political reasons. In all, seven prosecutors would resign to avoid taking a step they saw as deeply unethical.

Mr. Bove gave them an hour to make up their minds. The nearly 20 lawyers on the video call were unnerved, aware that the decisions might eviscerate their ranks and damage the department’s credibility. Some had already written their resignation letters. But a senior member of the team volunteered to sign, in part to spare his younger colleagues.

This article, based on interviews with people with knowledge of the events, offers the fullest account yet of that fraught hour. It revealed the determination of President Trump’s appointees to ram through a top-down command that ran counter to the professional standards of career lawyers and challenged the independence of the department. All spoke on the condition of anonymity for fear of retribution.

In demanding the case be dropped, Mr. Bove claimed that the timing of Mr. Adams’s indictment around nine months before the city’s primary gave “appearances” of political interference, and aiding a mayor who wanted to help deport undocumented immigrants outweighed convicting him of taking bribes. Mr. Bove concluded, according to the court filing in question, that “continuing these proceedings would interfere with the defendant’s ability to govern in New York City, which poses unacceptable threats to public safety, national security and related federal immigration initiatives and policies.”

Mr. Bove and Attorney General Pam Bondi have argued that dropping the charges against Mr. Adams is part of a broader effort to end the “weaponization” of the department by reining in excesses of the Biden administration. A Justice Department spokesman declined to comment.