WASHINGTON — When the deputy attorney general, Jeffrey A. Rosen, testified at his confirmation hearing in April 2019, he seemed to pledge to keep politics out of law enforcement decisions, telling the Senate: “I would expect in all prosecutorial matters to proceed on the facts and the law and not any improper political influences.”
But two months later, Mr. Rosen sent an unusual letter to prison officials who had planned to send President Trump’s former campaign chairman Paul Manafort to the notorious Rikers Island prison while awaiting a state trial after he was prosecuted on federal crimes, as similar convicts are routinely handled. After Mr. Rosen’s intervention, they changed course and housed Mr. Manafort in a less unpleasant place.
Mr. Rosen has kept a low profile, but with Attorney General William P. Barr’s pending resignation, he is set to be the nation’s top law enforcement official for the delicate final month of Mr. Trump’s presidency. It will be an extraordinary responsibility for a man who has no prosecutorial experience — and who has participated in several decisions in which the department took steps that favored the president’s friends or punished his perceived enemies.
In a statement the Justice Department released Tuesday evening, Mr. Rosen said he was “honored at the trust and confidence” that Mr. Trump had placed in him to serve as acting attorney general after Mr. Barr departs, and he said he would “continue to focus the implementation of the department’s key priorities,” including “maintaining the rule of law.”
Whatever his inclinations, his time as attorney general will be brief, noted Samuel Buell, a former federal prosecutor who teaches at Duke University School of Law. He added that if Mr. Rosen were to issue any “off the wall” edicts at the Mr. Trump’s request, career department employees could try bureaucratically to slow them.
“With so little time left, what is it an attorney general can do with a stroke of his pen?” Mr. Buell asked. “A sustained effort to steer a department in a particular direction takes more than a month.”
A corporate lawyer who spent most of his career with Kirkland & Ellis, Mr. Rosen will be an unusual attorney general because he has no experience as a prosecutor. (Mr. Barr, despite twice serving as attorney general, has none either.) Mr. Rosen had worked as general counsel of the Transportation Department and then at the White House’s Office of Management and Budget during the George W. Bush administration.
When Mr. Trump took office, he appointed Mr. Rosen as the No. 2 official at the Transportation Department. There, he pushed to roll back tailpipe emissions rules to let the automotive industry manufacture cars that will put more greenhouse gas pollution into the atmosphere. In 2019, when Mr. Barr became attorney general, he asked Mr. Trump to nominate Mr. Rosen — with whom Mr. Barr had worked at Kirkland & Ellis — as his deputy.
Mr. Rosen has had a largely quiet tenure, staying in Mr. Barr’s shadow. Mr. Barr has adopted a lightning rod style, giving openly culture-war speeches and taking personal responsibility for politically tinged interventions, like reducing a recommended prison sentence for another convicted presidential favorite, Roger J. Stone Jr., and trying to drop a case against a third, Michael T. Flynn, even though he had pleaded guilty. (Mr. Trump ultimately commuted Mr. Stone’s sentence and pardoned Mr. Flynn.)
Mr. Barr’s record of politicizing the Justice Department, however, has been complicated by his approach to the election. He publicly rejected Mr. Trump’s spurious claims of election fraud and kept the department out of the dozens of failed lawsuits the Trump campaign and allies have brought seeking to subvert the outcome.
It has also emerged that Mr. Barr knew that President-elect Joseph R. Biden Jr.’s son Hunter Biden was the subject of a money laundering investigation that appears to have subsided and a tax investigation, but he respected department norms and did not make that information public before the election despite open demands from Mr. Trump to damage Mr. Biden. And since the disclosure of those inquiries, Mr. Barr resisted Mr. Trump’s pressure to appoint a special counsel for the Hunter Biden inquiry.
Mr. Barr’s resistance to Mr. Trump’s demands that he use the department to subvert the election strained their previously close relationship, leading Mr. Trump to bully Mr. Barr on Twitter over the weekend and culminating with Mr. Barr’s submission of a resignation letter on Monday. It will now fall to Mr. Rosen to decide whether to maintain Mr. Barr’s stances on such issues during what may be a fraught endgame for Mr. Trump.
It will be an intense change of pace for a lawyer mainly versed in business and administrative law issues, although he has sometimes strayed into the murkier waters of the Trump era.
In late summer 2019, not long after his intervention that helped Mr. Manafort stay out of Rikers Island, Mr. Rosen convened a meeting with lawyers for the former F.B.I. deputy director Andrew G. McCabe regarding accusations that he had lied to internal investigators about dealings with the news media.
Asking a grand jury to indict Mr. McCabe would be in line with the desires of Mr. Trump, who had repeatedly attacked him; he was the acting director of the F.B.I. when investigators opened an inquiry into whether the president obstructed justice. But Mr. McCabe’s lawyers urged Mr. Rosen to shelve the case, arguing that their client had not intentionally lied and noting that in any case, false statements made during internal inquiries at federal law enforcement agencies are typically punished administratively, not by criminal prosecution.
Mr. Rosen rejected their appeal, which would normally be a precursor to an indictment. (In a twist, the grand jury did not indict Mr. McCabe. It remains unclear whether prosecutors asked for an indictment and the jury balked, or whether prosecutors — seeing the reaction of the jurors to the evidence and arguments — pulled the case back.)
In early 2020, when Mr. Barr intervened in the sentencing of Mr. Stone and moved to take over politically delicate national security cases in the U.S. attorney’s office in Washington, he assigned aides to Mr. Rosen to review how career prosecutors had been handling those investigations.
But while Mr. Rosen was involved as well, Mr. Barr portrayed himself as the official making those decisions, keeping the spotlight off his deputy.
In June, according to a person familiar with internal deliberations, Mr. Rosen quietly quarterbacked a government lawsuit that unsuccessfully asked a judge to order Mr. Trump’s former national security adviser John R. Bolton to pull back his White House memoir, which presents a negative account of the president and had already been printed. (The Wall Street Journal earlier reported Mr. Rosen’s behind-the-scenes role.)
As the year progressed, however, Mr. Rosen began to attract attention by publicly staking out conservative positions on matters like capital punishment and aggressively going after protesters who use violence.
In July, when the Trump administration began carrying out executions of federal death row inmates for the first time in 17 years, Mr. Rosen stepped forward as a face of the policy decision, writing an opinion article in The New York Times that the resumption of capital punishment was legally justified.
“If death sentences are going to be imposed, they cannot just be hypothetical; they eventually have to be carried out, or the punishment will lose its deterrent and retributive effects,” he wrote.
And in September, Mr. Rosen threw his support behind Mr. Barr’s threat to charge perpetrators of violence amid Black Lives Matter demonstrations with sedition, a word that connotes plots to overthrow the government. In a memo to prosecutors, he rejected criticism of that threat as an overreach, noting that the law also covers seizing federal property or hindering the execution of federal laws outside the context of attempted revolutions.
“Those who have actually read the statute recognize that the text” of the sedition law, Mr. Rosen wrote, “could potentially apply to some of the violent acts that have occurred.”
Still, Mr. Rosen’s expertise is business-related law, including antitrust; early in his career, Mr. Rosen represented Netscape Communications in the antitrust battle against Microsoft over web browsers. And to date, Mr. Rosen’s highest-profile action as a Justice Department official was overseeing the antitrust lawsuit against Google he announced in October.
While there were complaints, including within the department, that he had rushed out that case before it was ready, he noted in an interview with The Times that there was bipartisan support for the action itself.
“At the end of the day, it doesn’t matter what politicians say,” Mr. Rosen said. “It matters what the facts and the economic analysis and the law are. That guides our decisions.”
Katie Benner contributed reporting.