During a radio interview in November 2017 Donald Trump talked openly about his frustration with the fact that “because I’m the president of the United States, I am not supposed to be involved with the justice department … I’m not supposed to be doing the kind of things that I would love to be doing.”

The Department of Justice’s sudden about-face in the Roger Stone case is just the latest indication that Trump no longer will put up with that particular frustration and will, when it suits him, weaponize that department.

On Monday, federal prosecutors filed a sentencing memo recommending that Stone serve a jail term of seven to nine years after having been found guilty last year of crimes including obstruction of justice, lying to Congress and witness tampering. That recommendation hewed closely to the federal sentencing guidelines.

In the early hours of Tuesday morning, Trump tweeted a scathing rebuke of that recommendation, claiming: “The real crimes were on the other side, as nothing happens to them. Cannot allow this miscarriage of justice!”

Then, on Tuesday afternoon, the justice department made an abrupt turn, amending the previously filed memo and arguing against its own previously articulated arguments, claiming that the earlier recommendation was too harsh.

This action led to the resignation of four career prosecutors.

Trump’s intervention in the Stone case and the attorney general’s obsequious eagerness to please the president marks a new and particularly dangerous stage in Trump’s campaign to politicize American justice.

Indeed, it is precisely what the government’s original sentencing memo labelled Stone’s “contempt for this court and the rule of law” that prompted Trump to rally to his defense.

On Wednesday morning Trump again turned to Twitter and labelled the prosecutors who resigned “Mueller people”.

He congratulated his attorney general, William Barr, “for taking charge of a case that was totally out of control and perhaps should not have even been brought” and linked the Stone case to his continuing effort to discredit the special counsel Robert Mueller’s investigation which he again called a “Scam” that “was improperly brought & tainted”.

Because of their professionalism and commitment to doing justice under law, federal prosecutors long have been granted wide berth to make charging decisions and decide whether to offer plea bargains. That also is why judges accord considerable deference to prosecutors’ sentencing recommendations.

Trump and Barr will not allow professionalism or the rule of law to stand in their way

Today Trump and Barr will not allow professionalism or the rule of law to stand in their way. They recognize or respect no boundaries between law and politics. Indeed, Trump is following the playbook of autocrats who use law as “a weapon to defeat opponents while protecting his own supporters’ lawbreaking”.

Trump’s tweets offer further evidence that, in cases in which he has a personal or political interest, he wants to turn federal prosecutors into political hacks whose prosecutorial judgments cannot be disentangled from the president’s whims.

Trump and Barr are treating prosecutorial decisions as instances of unfettered, presidential prerogative, a prerogative like the clemency power. While courts have insisted that prosecutors cannot use their power in a selective, discriminatory or abusive manner, they have imposed no such limits on the president’s power to grant pardons and reprieves.

According to an 1866 decision of the US supreme court, that power is “unlimited”, extending to “every offense known to the law”.

Others have been even more explicit about the vastness of the clemency power, saying: “An executive may grant a pardon, for good reasons or bad, or for any reason at all, and his act is final and irrevocable. Even for the grossest abuse of this discretionary power, the law affords no remedy.”

And Trump himself proudly proclaims that “all agree the US president has the complete power to pardon” while bypassing long-established justice department procedures to pardon a rogues’ gallery of the notorious and the well-connected.

No wonder he calls the clemency power a “beautiful thing”.

The Stone case evidences Trump’s norm- and institution-destroying impatience with anything that prevents him from making the prosecutorial power into a “beautiful thing” that can be used to protect his friends and punish those who dare to oppose him.

Speaking to a 1940 gathering of federal prosecutors, the then attorney general and future supreme court justice Robert Jackson warned of the perils of prosecutorial animus or favoritism. “It is in this realm in which the prosecutor picks some person whom he dislikes or desires to embarrass, or selects some group of unpopular persons and then looks for an offense,” Jackson warned, “that the greatest danger of abuse of prosecuting power lies. It is here that law enforcement becomes personal, and the real crime becomes that of being unpopular with the predominant or governing group, being attached to the wrong political views, or being personally obnoxious to or in the way of the prosecutor himself.”

In that same speech, Jackson reminded his listeners that “the prosecutor has more control over life, liberty and reputation than any other person in America”. When Trump interferes with the proper exercise of that power, as he did in the Stone case, he puts at risk the life, liberty and reputation of every American.