Among the many Trump Administration officials who are likely to be targets of the Democrats’ formal impeachment inquiry, one of the most central is the Attorney General, William Barr. According to Justice Department officials and the whistle-blower complaint about President Trump’s phone call with the Ukrainian President, Barr knew of Trump’s effort to get Ukraine to interfere in the 2020 election by investigating a possible rival, former Vice-President Joe Biden, and of the Department’s subsequent suppression of the whistle-blower complaint. On Friday, House Speaker Nancy Pelosi accused Barr of being part of a “coverup of the coverup,” and signalled that the Attorney General will be a focus of the investigation. “I do think the Attorney General has gone rogue—he has for a long time now,” Pelosi told CNN. “And, since he was mentioned in all of this, it’s curious that he would be making decisions about how the complaint would be handled.”

The record of Barr’s Justice Department supports Pelosi’s assessment. When the complaint arrived at the Department, the Office of Legal Counsel ruled that it was not an “urgent concern”—a decision questioned by Democrats—and therefore should not be handed over to Congress. And then, in a more surprising move, the Justice Department’s Criminal Division declined to investigate the whistle-blower’s allegation that the President had engaged in criminal conduct. Department officials played down Barr’s role, saying that he was “generally knowledgeable” of discussions about the O.L.C. decision to find the complaint not urgent, but was not involved in the Criminal Division’s decision to decline to investigate the allegation. They also maintain that the Department’s decisions about the complaint were based on legal considerations, not political ones.

The distinction between legal and political considerations in these cases, though, is not so simple. Both the O.L.C. and the Criminal Division are led by Trump appointees, who, like Barr, are generally defenders of the power of Presidents to act unilaterally and limit congressional involvement. Human-rights groups questioned the role of Steven Engel, the head of the O.L.C., in the drafting of a 2007 Justice Department legal memo that authorized the use of interrogation techniques—such as sleep deprivation for up to ninety-six hours and forcing detainees to wear diapers—that are widely considered torture. Brian Benczkowski, who leads the Criminal Division, has been criticized by Democrats for having little experience prosecuting cases and close political ties to Trump’s former Attorney General, Jeff Sessions, and other conservative Republicans.

Mary McCord, a former senior Justice Department official and a professor at Georgetown Law School, questioned the Criminal Division’s decision not to investigate. “I find it very surprising that Justice Department lawyers would find that there’s nothing here worth exploring,” McCord, who led the Department’s National Security Division from 2016 to 2017, told me. McCord, who has also prosecuted government officials on corruption charges, added that a request from Trump to Ukraine for interference in the 2020 election did not, as some Republicans have maintained, need to be explicit. “It’s ridiculous to expect that you’re going to see that kind of language,” she said. “It’s what you see in other corruption cases. You see these kinds of somewhat guarded language.”

Richard Hasen, a law professor at the University of California, Irvine, who specializes in election law, told the Washington Post last week that the Criminal Division’s failure to investigate the case was “laughable.” He criticized the Criminal Division’s finding that the value of a Ukrainian government investigation of Biden could not be quantified and therefore could not be investigated as a possible campaign-finance-law violation. “You’re talking about information on a potential rival that could be used in a presidential campaign, a presidential campaign which likely would run into the billions of dollars,” Hasen said. “I don’t think there’s any question that a prosecutor could go forward with the theory.”

Barr, who served in his current role previously, under George H. W. Bush, is only the second American to have served twice as Attorney General. When he replaced Sessions, in February, 2019, he was seen as a skilled lawyer and experienced Washington hand who could act as a restraining influence on Trump. Since he took office, however, Barr has become one of Trump’s closest aides and the focus of complaints that he is the most politicized Attorney General in decades. Critics accuse him of repeatedly using his authority to benefit the President politically, helping Trump mount an unprecedented assault on Congress’s oversight of the executive branch and the President.

First, in March, Barr produced a misleading summary of the special counsel Robert Mueller’s final report on the Russia investigation, in which Barr cleared the President of wrongdoing. “I have concluded that the evidence developed during the Special Counsel’s investigation is not sufficient to establish that the President committed an obstruction-of-justice offense,” Barr wrote. Mueller, in fact, had found ten potential episodes of obstruction of justice, but left it up to Congress to decide whether Trump was guilty. When congressional Democrats tried to investigate the potential acts of obstruction by subpoenaing the Trump aides who witnessed it, Barr’s Justice Department issued a legal opinion that the staffers were not required to testify before Congress.

In recent months, Barr has amplified Trump’s threats to law-enforcement and intelligence officials. During congressional testimony in April, Barr said that the F.B.I. may have spied on Trump, giving credence to conspiracy theories spread by the President that the F.B.I. had improperly wiretapped Trump Tower during the 2016 campaign, a claim flatly denied by F.B.I. officials. “Spying on a political campaign is a big deal,” Barr told senators. “I think spying did occur. The question is whether it was adequately predicated.” A month later, Trump announced that Barr was carrying out a sweeping investigation of the origins of the F.B.I.’s Trump-Russia investigation. Democrats said that Barr’s actions sent a message to law-enforcement and intelligence officials that they would face retaliation if they investigated Trump.

The Ukraine phone call sets another precedent. In his conversation with the Ukrainian President, Volodymyr Zelensky, Trump said that Barr was a participant in the President’s effort to get Ukraine to investigate Biden. Trump, of course, could have been lying to Zelensky. Trump also may never have followed up with Barr after the call. Either way, the President has smeared Barr and fuelled calls for the Attorney General to be investigated. Barr, who claims he never spoke with Trump about Zelensky, now faces a decision. Will he uphold his own reputation or that of the President, who is impugning him?

Barr might recall the example of John Mitchell, who, in 1975, became the first—and only—former Attorney General of the United States to be sent to prison. Mitchell served as Richard Nixon’s Attorney General from 1969 to 1972, and then as chairman of Nixon’s 1972 Presidential reëlection campaign. As campaign chairman, he oversaw the Watergate break-ins and then participated in the coverup. Unlike other aides who broke with Nixon and implicated the President, Mitchell declined to reveal his conversations with the President. He was convicted by a jury of his peers of conspiracy, obstruction of justice, and perjury for his role in Watergate. Mitchell served nineteen months in federal prison before being released, for medical reasons.