The Attorney General of the United States takes the same oath of office that I took over three decades ago when I became an Assistant United States Attorney for the Southern District of New York. It is an oath to "support and defend the Constitution of the United States." The role of the Attorney General, which flows from that oath, is to uphold the rule of law, to represent the best interests of the United States, and to pursue justice. He or she is the chief attorney for our country, not the attorney for the office of the presidency or for any particular president. The current occupant of the White House, however, has a different view of the job.

When, against President Trump's wishes, then Attorney General Jeff Sessions recused himself from the Justice Department's investigation into Russian interference in the 2016 election, Trump famously complained, "Where's my Roy Cohn?" He was referring, of course to his mentor, the famed New York attorney and socialite known primarily for being a fixer and a booster of Senator Joseph McCarthy who was ultimately disbarred for misconduct shortly before his death in 1986.

The thrust of Trump's complaint was clear. In his untutored and contorted view, the job of the Attorney General of the United States is to have his back and to fix his legal problems, much as his former personal attorney Michael Cohen had when the latter arranged for secret pay-offs to silence two women with whom Trump allegedly had had extramarital affairs (acts which resulted in Cohen's conviction on criminal charges that specifically implicated the president). If Sessions would not do his dirty work, the president was determined to find someone who would, and after firing Sessions, he found that person in William Barr, the current Attorney General.

For his part, Barr has openly abandoned any pretense of acting in the nation's best interest and has instead acted as Trump's "Roy Cohn" or his new Michael Cohen — take your pick. The litany of his abuses of power on behalf of the president is worth rehearsing here.

Upon taking office in February 2019, Barr refused to recuse himself from Russia/Mueller Investigation, notwithstanding that in June of 2018 he had sent a 20 page unsolicited legal memorandum to the Department of Justice — which he separately sent to and discussed with the president's legal team — in which he perversely claimed that Mueller had no authority to investigate the Trump for obstruction of justice. When Mueller filed the report of his investigative findings with Barr, the latter summarized them in a letter to Congress that can only be characterized — charitably — as a whitewashing of much of the wrongdoing that the former had uncovered. In fact, when a redacted version of the report was released in April of 2018, fact-checkers and news outlets reported that Barr had deliberately mischaracterized the Mueller report and its conclusions.

And, as recently as May of this year, in a Freedom of Information Act lawsuit seeking disclosure of the entire Mueller Report, Judge Reggie B. Wilson of the United States District Court for District of Columbia (nominated to that post by President George W. Bush) found that Barr had advanced a "distorted" and "misleading" account of the report's findings such that his statements regarding the purported reasons for prior redactions of the report lacked credibility.

Not content with mischaracterizing the report's findings and conclusions, Barr has engaged in a real witch-hunt by, in May of 2019, appointing District of Connecticut United States Attorney John Durham to investigate the origins of the Russia investigation. And he has done so notwithstanding the conclusion of Michael Horowitz, the Justice Department's Inspector General, that the investigation of Russian interference in the 2016 election was appropriate and the overwhelming consensus of the intelligence community that the evidence of such interference was and is indisputable. More than a year after Barr and Durham's globe-hopping investigation, no one has been charged with crime.

But it does not end there. Barr has taken unprecedented steps to quash or lessen the impact of prosecutions brought by Mueller's team. When, in February of this year, career Justice Department prosecutors recommended a seven- to nine-year sentence for celebrated political dirty trickster and Trump friend Roger Stone, who had been convicted of lying to Congress about Russian interference in the 2016 election, Trump tweeted, "Cannot allow this miscarriage of justice!" Later that very same day, Barr responded by filing a new sentencing memorandum stating that the initial recommendation was too harsh and that it "would not be appropriate or serve the interests of justice" notwithstanding that it was the range indisputably called for by federal sentencing guidelines. The four career prosecutors who had submitted the initial memorandum immediately resigned, and Trump publicly tweeted his thanks to Barr for intervening in the case as he had.

Likewise, in February of this year, notwithstanding that Michael Flynn, Trump's first national security advisor, was fired for making false statements to Vice President Mike Pence about his contact with Russian officials, and that Flynn had pleaded guilty to making false statements about the very same subject matter to the FBI agents who had interviewed him in connection with the Russia investigation (and had admitted under oath during his guilty plea proceeding that he had done so), Barr appointed Jeffrey Jenson, the chief federal prosecutor in St. Louis, to investigate the Justice Department's/FBI'S investigation of Flynn. In May of this year, much to Trump's delight, Barr moved to dismiss the Flynn prosecution prior to sentencing, claiming — ludicrously — that Flynn's statements were not material to the FBI's investigation in connection with which he was questioned.

Barr thought he could easily slip one past Judge Emmet Sullivan, who is presiding over Flynn's case. But he miscalculated — badly. Sullivan appointed the universally respected retired federal judge John Gleeson to investigate Barr's motion for dismissal. Just weeks ago Gleeson filed a 73 page brief in the case, stating that Barr's attempt to deep-six the Flynn prosecution was a "gross abuse of prosecutorial power" and that the Attorney General had given special treatment to a presidential ally, thereby undermining public confidence in the rule of law. On June 24, a divided panel of the D.C. circuit ordered Judge Sullivan to dismiss the case, but the panel's decision is likely headed for en banc and eventually Supreme Court review.

Finally, just last week, Barr, presumably acting at Trump's behest, fired Geoffrey Berman, the Acting United States Attorney for the Southern District of New York, a Republican whom Barr had initially appointed and whose interim status was later confirmed by the Board of Judges in the District (and, full disclosure, a former colleague of mine at the U.S. Attorney's Office). It is worth noting that as of this writing, neither Barr nor Trump has proffered a credible reason for this Friday night massacre. Neither can claim Berman was incompetent. In fact, he was reportedly offered the position of chief of the Justice Department's Civil Division if he would just leave his position quietly.

The only plausible reason for Berman's sacking would appear to be his record as U.S. Attorney including: his prosecution of Michael Cohen, Trump's prior attorney/fixer; his prosecution of two associates of the president's private lawyer Rudy Giuliani, who were said by prosecutors to have been involved in the effort to recall the United States ambassador to Ukraine, Marie Yovanovitch; his investigation of Giuliani himself, in connection with allegations stemming from his lobbying practice; and his indictment, against Trump's personal wishes, of Halkbank, a Turkish state-owned bank, on charges that it conspired to undermine the United States Iran sanctions regime.

There is much else one can say about Barr and about he has perverted the administration of justice during his most recent tenure as attorney general. But the instances set forth above are noteworthy because they are part of a clear pattern. The findings of the Mueller report showed there was massive Russian interference in the 2016 presidential election, almost all of it on behalf of Trump. Those findings were an embarrassment to Barr's boss and, more importantly, a huge blow to his boss's incredibly fragile ego. In response, Barr, doing Trump's bidding, set out upon a course to do all he could to discredit the Mueller investigation. He misrepresented its findings, is still pursuing a vengeful and baseless investigation into Mueller's investigators, and has sought to undermine two of Mueller's most important prosecutions. His firing of Berman is of a piece with his treatment of the Mueller investigation. Berman went after Trump associates, and so Berman had to go. And he had to go before he could do any more damage to Trump's reputation.

It is clear beyond peradventure that Barr views his job not as supporting and defending the Constitution of the United States as he swore to do when he took the oath of office, but rather as supporting and defending the man who appointed him to the office he holds, Donald Trump. In doing so, he has engaged in gross abuses of power, and the damage he has done to the integrity of the Justice Department and to the rule of law is incalculable. It's time for him to go. If he will not resign or be fired by the president — either of which seems highly unlikely — then he should be impeached and removed by Congress, pursuant to its power under Article II, Section 4 of the Constitution, before he can do any more damage. If the House impeaches Barr, the Senate may well acquit him as it did Trump. But it will be worth the effort, if for nothing else as a statement of first principles and moral clarity. As Edmund Burke once famously observed, "The only thing necessary for the triumph of evil is for good men to do nothing."

Elliott B. Jacobson served as an Assistant United States Attorney for the Southern District of New York from 1985 to 2017 and was a Wasserstein Public Interest Fellow at the Harvard Law School.