Former President Trump is rightly being criticized for politicizing the Department of Justice. Given its awesome powers, DOJ must be above politics and not used by a president to harass, much less prosecute, his political opponents.
Trump’s actions have drawn understandable comparisons to Richard Nixon, who was forced to resign the presidency over Watergate and whose attorney general, John Mitchell, served 19 months in prison as a result of his related crimes.
But there’s at least one other president who politicized the DOJ and who deserves to be roundly criticized for having done that: John F. Kennedy.
Some years ago I asked my colleague and friend, Stanford Professor of History Barton J. Bernstein, about a related matter. With his encyclopedic knowledge and photographic memory, he told me to look in Ben Bradlee’s book on JFK. If memory serves me, Bart even told me the page numbers on which I could find the following, highly relevant excerpt:
June 14, 1962 … The occasion was a party given for the president [JFK] by Jean and Steve Smith. About 10:30 P.M. the president stood up to make a toast …. to the attorney general [his brother, Robert Kennedy] … and went on to describe how he had been talking that afternoon with Jim Patton, president of Republic Steel. [JFK was in the middle of a fight with the steel companies, trying to get them to lower prices.]
“I was telling Patton what a son of a bitch he was,” the president said with a smile, referring obliquely to his now famous remark that all businessmen were sons of bitches. He waited with that truly professional sense of timing instinctive to the best comedians, and he went on “… and he was proving it.”
Patton asked me ‘Why is it that all the telephone calls of all the steel executives in all the country are being tapped?’ And I told him that I thought he was being wholly unfair to the attorney general and I’m sure that it wasn’t true.
And he asked me, ‘Why is it that all the income tax returns of all the steel executives in all the country are being scrutinized?’ And I told him that, too, was wholly unfair, that the attorney general wouldn’t do any such thing.
And then I called the attorney general and asked him why he was tapping the telephones of all the steel executives and examining the tax returns of all the steel executives … And the attorney general told me that was wholly untrue and unfair.”
And then another Stanislavsky pause. “And of course, Patton was right.” At this point Bobby interrupted from the floor to explain in mock seriousness: “they were mean to my brother. They can’t do that to my brother.” 
The above is not intended to excuse Trump’s misdeeds. If guilty of a crime, he should be prosecuted as any other citizen would be. Rather, I hope to help prevent future politicization of the DOJ and to bring deserved condemnation to any past acts, even if they were perpetrated by presidents our nation reveres. Great presidents do not use the DOJ to go after their political enemies.
Clear rules are needed to prevent misuse of DOJ and the above examples show that applies to both Democratic and Republican presidents. We are fortunate that Merrick Garland has a reputation for keeping the department above politics, but clear rules would be welcome even in his stewardship of DOJ.
 Benjamin C. Bradlee, Conversations With Kennedy, Norton & Co., New York, 1975, pp. 110-112.
Bradlee was the executive editor of the Washington Post when it covered the Watergate scandal. It is surprising that Bradlee would disclose the above incident, especially after he was so instrumental in exposing Nixon’s similar conduct in Watergate. A New York Times review of the book gives a possible explanation:
Bradlee, the editor, is tacitly clicking his tongue at Bradlee, the boy‐reporter, reminding himself and everyone else of his close call with the seductiveness of high office—the glamorous trappings, the convenience, and especially the arrogance that inevitably accompanies it.