The Redskins fired coach Mike Shanahan on Monday after his fourth season with the team. Washington went 3-13 and finished last in the NFC East this year. (John McDonnell/The Washington Post)

Absolute power corrupted Mike Shanahan absolutely.

It wasn’t just mismanagement of Robert Griffin III and the quarterback’s injury that cost the Redskins coach his job. Nor was it the earlier failures with Donovan McNabb and Albert Haynesworth.

It wasn’t just poor clock management or his hiring of son Kyle Shanahan to run the offense. Switching to a 3-4 defense that seldom worked wasn’t the only reason, either.

It wasn’t even the drafts — which weren’t as good as expected. And it wasn’t Shanahan staking his reputation on quarterbacks Rex Grossman and John Beck being legitimate NFL starters when they weren’t.

In the end, it was a combination of everything — including a 24-40 record — that led to Shanahan being the latest overpaid, overhyped coach to be fired under owner Dan Snyder.

Shanahan’s narcissism never wavered — even though he led the Redskins to only one playoff game in his four years.

Shanahan thought his way was the only way when picking players, overruling staff and benching Griffin. Like predecessor Marty Schottenheimer, Shanahan was finally fired by Snyder after failing to merit his inflated ego.

Total control ruined another Redskins coach. An NFL team needs checks and balances just like the federal government. Otherwise, autocracies ultimately fail. Shanahan lasted this long because Snyder feared he’d be called meddlesome after earlier rash pink slips.

For the Redskins to become consistent winners under Snyder, the front office structure must change. Washington needs a real general manager. Not a puppet that fronts for Snyder. Not someone who worries more about alumni and uniform colors. Not a consultant ready to emerge from the shadows.

Snyder needs a legitimate personnel man with ruling power over the coach for picking players. Oh, that’s not saying the coach has no say (Steve Spurrier once showed that unwanted first-round passers can sit on the bench). But good teams find that marriage between the GM and coach like the Redskins once enjoyed with Bobby Beathard and Joe Gibbs. When Gibbs didn’t want Joe Jacoby, Beathard told him to trust the GM. Now Jacoby is a Hall of Fame contender.

The owner needs to choose a GM first, then let the latter come up with coaching candidates. Snyder still gets final say, but he should respect the GM’s recommendation. Otherwise, don’t hire that person as GM. Then-owner Jack Kent Cooke thought Beathard was nuts for wanting Gibbs and nearly fired both after an 0-5 start in 1981. Gibbs later won three Super Bowls.

Snyder has used every combination possible over 14 years except an equally strong GM and coach. It’s time to try it.