MICHAEL GOODWIN: Why James Comey had to go.

The suddenly-former FBI boss was long cavalier about making enemies among both Democrats and Republicans, as if going rogue repeatedly proved his rectitude. On occasion it did, but Comey increasingly wore his self-righteousness on his sleeve, confident he was too big to fire.

That was his fatal mistake. And it’s why Trump made the right decision to show him the door.

Comey’s power-grabbing arrogance is why I called him “J. Edgar Comey” two months ago. His willingness to play politics, while insisting he was above it all, smacked of Washington at its worst. He was the keeper of secrets, until they served his purpose.

As such, the president did to Comey what no president had the courage to do to J. Edgar Hoover. Five presidents wanted to fire Hoover, with Harry Truman accusing him of running a police state and of blackmail. But all were afraid of Hoover, so he died in office.

Trump acted before Comey could get that kind of lifetime protection, which has no place in American democracy. At our best, we are a nation of laws, not of people who accumulate power and ruthlessly wield it without accountability.

The president didn’t have just one good reason to act. He had a choice among many.

The proximate cause was lying to Congress, which isn’t just enough to be shown the door — it’s nearly obligatory.