In part, that may be because the precedent for an FBI director to be removed from office is short. In fact, it’s only happened once before.

To some extent, that’s a function of the age of the agency. The Federal Bureau of Investigation was created within the Department of Justice by Attorney General Charles Bonaparte in 1908 at the urging of Stanley Finch, who pushed for Justice to have its own investigatory team. Finch became the first head of the Bureau of Investigation.

It’s also due in large part to J. Edgar Hoover, who ran the agency for nearly half of its existence. As of Comey’s firing, Hoover was the director of the bureau for 44 percent of the time that there has been an FBI.

There simply haven’t been that many directors of the FBI. Only 11 people (all men) have held the position; seven more have served as acting directors in between confirmations. Of those 11, only one, besides Comey, has been fired: William Sessions, who served from 1987 to 1993.

The Post’s 1993 story explains why Sessions was terminated — and why it happened when it did:

[President Bill] Clinton’s action ended an agonizing public debate that began last January when a scathing report from the Justice Department’s Office of Professional Responsibility (OPR) accused Sessions of numerous ethical lapses. Although a Clinton spokesman immediately described the report as “disturbing” and administration officials concluded within weeks of taking office that Sessions had to be replaced, the White House permitted him to stay on for months — a delay that senior FBI officials say badly demoralized the bureau and exacerbated an already painful rift between the director and top bureau managers. . . .
Sessions’s future was thrown into doubt earlier this year when the OPR report found that he had abused his office by setting up official appointments to justify charging the government for personal travel, improperly billed the FBI nearly $10,000 for a fence around his home, and refused to turn over documents on his $375,000 home mortgage, which investigators said they suspected involved a “sweetheart deal.”

Worth noting for future trivia contests: Comey was ostensibly fired for his handling of the investigation into the wife of the president who last fired an FBI director.

Even Hoover — whose tenure at the FBI has become known as much for his willingness to stretch the boundaries of decency and the law — was never fired. Presidents Truman and Kennedy had entertained the idea (about 20 and 40 years into Hoover’s tenure, respectively), but Hoover’s political strength made doing so impossible. Hoover died while still holding the position — shortly before the Nixon White House became mired in Watergate.