When President Richard Nixon decided in late October 1973 to force out the attorney general and replace him with someone who would fire the special prosecutor haunting his life, he went through the chain of command until he got to the third person in line, the solicitor general, who did the deed. Now here we are again, with another president wanting to be rid of an investigation by a special counsel that threatens his presidency.

But rather than follow the regular order, as Nixon had, President Trump selected as acting attorney general a lackey who had been chosen as chief of staff to the attorney general because of his TV appearances as a private citizen in which he echoed the president’s position on the special counsel’s investigation into Russia’s role in the 2016 election. Among other things, he’d parroted Mr. Trump’s obsessive line, “There was no collusion.” It has been broadly assumed that this man would, one way or another, end the special counsel’s investigation.

Whether, as some legal scholars argue, Mr. Trump’s choice was unconstitutional, since the new acting attorney general has never been confirmed by the Senate, or was simply unwise since his choice was blatantly self-serving, the differences in the ways the two presidents have approached getting rid of an inconvenient prosecutor are informed by their different backgrounds.

Nixon, a lawyer who had been a member of the House of Representatives, a senator and a vice president, was more accepting of the political order. Mr. Trump, with no government experience, and little knowledge of how the federal government works, has been a free if malevolent spirit, less likely than even Nixon to observe boundaries.