Pennsylvania Lawmaker Played Key Role in Trump’s Plot to Oust Acting Attorney General

The plan that Mr. Perry devised with Mr. Clark set off a crisis at the Justice Department. When Mr. Clark approached Mr. Rosen with the Georgia letter at the end of December, Mr. Rosen refused to send it, according to four former administration officials. On Jan. 3, Mr. Clark notified Mr. Rosen that he would be taking his job at Mr. Trump’s behest.

As Mr. Rosen prepared to meet Mr. Trump later that day and fight for his job, his top deputies, including the acting deputy attorney general, Richard P. Donoghue, and his outgoing chief of staff, Patrick Hovakimian, convened the department’s senior leaders on a conference call, according to five former officials with knowledge of the call.

They told the department leaders that Mr. Rosen’s job was in jeopardy because of Mr. Clark’s machinations and said they would resign if Mr. Rosen was removed. They ended the call by asking their colleagues to privately consider what they would do if that happened. Over the next 15 minutes, all of them emailed or texted Mr. Hovakimian, saying that they would quit.

While Mr. Rosen, Mr. Donoghue and other top department and White House lawyers spent nearly three hours with Mr. Trump and Mr. Clark, debating the merits of sending the letter to Georgia lawmakers, Mr. Hovakimian — in anticipation of Mr. Rosen’s removal — drafted an email to the department’s senior leaders, including those who were not aware of what was transpiring at the White House, according to two people briefed on the letter.

In it, he explained that Mr. Rosen had resisted Mr. Trump’s repeated entreaties to use the department’s law enforcement powers for improper ends and that the president had removed him, according to a person who reviewed the email. He wrote that he and Mr. Donoghue were resigning immediately and encouraged his colleagues to think hard about what they would do and to always act in the interests of the United States.

When Mr. Hovakimian received word that Mr. Rosen had been allowed to stay, he drafted a new email that he sent to the anxiously awaiting officials: Mr. Rosen and the cause of justice had won.

Maggie Haberman contributed reporting from New York.