That's because his successor, by the law of averages, is unlikely to have a record as good as his. Shanahan is tied for 15th on the list of career NFL coaching victories. He won 62 percent of his games with the Broncos. That will be hard to match.

The list of legendary coaches succeeded by less-legendary coaches is long and distinguished. And, of course, undistinguished, too.

The most common reflex throughout the years has been to hire the departed legend's defensive coordinator. The Packers did this after Vince Lombardi, the Redskins after Joe Gibbs (the first time), the 49ers after Bill Walsh. Phil Bengtson and Richie Petitbon didn't work out so well, but George Seifert won two Super Bowls for the Niners. As in baseball, one out of three ain't bad.

Wade Phillips is the Forrest Gump of this category, having replaced his father, Bum, in New Orleans, Marv Levy in Buffalo, Bill Parcells in Dallas and Dan Reeves in both Denver and Atlanta. As it happens, he's not available to perform this stunt for a sixth time - at least, not at the moment.

Unfortunately, naming your defensive coordinator generally requires a respectable defense. The Broncos don't have one of those, so this option is out. Far from being a candidate to replace Shanahan, defensive coordinator and old friend Bob Slowik is possibly one of the reasons for his departure.

But the disappointing successor is not always a defensive coordinator. The Vikings replaced legendary Bud Grant with Les Steckel, an offensive assistant.

On the bright side, a step down is not inevitable. The Steelers replaced Chuck Noll with Bill Cowher, a young defensive coordinator from another organization. Compared with Noll's four Super Bowl championships in 23 seasons, Cowher's one in 14 still represents a decline, but, like Shanahan, he won 62 percent of his regular-season games.

The Cowboys replaced legendary Tom Landry with a hot young college coach, Jimmy Johnson of the University of Miami, who also happened to be a former college teammate of the man doing the hiring, Cowboys owner Jerry Jones. Landry won two Super Bowls in 29 years. Johnson needed only five seasons to win as many.

So it's possible that Broncos owner Pat Bowlen will be able to find a "10," to use his own description, to succeed the winningest coach in Broncos history, but the odds are against it. The history makes it likely a review of the won-loss records 10 years from now will make the Shanahan firing look like a bad idea.

But that doesn't mean it was. As usual, the numbers don't tell the whole story.

Bowlen's inability to articulate just why he chose to fire Shanahan now, after saying for years he could stay as long as he liked, had two possible ROOT causes.

One is his preference to keep private differences private. Shanahan is the same way. Even in his final news conference, he refused to discuss what went wrong with his 29th-ranked defense. To the end, he was not going to acknowledge mistakes or internal differences publicly.

It's been suggested that Bowlen wanted a reduction in Shanahan's executive portfolio or changes in his defensive staff. He denied both, but given the tight-lipped nature of the organization, that doesn't tell us much.

The other possible reason Bowlen didn't explain just why he fired his old friend is that he couldn't. When a single executive acquires all the power and titles within an organization, as Shanahan did with the Broncos, an arrogance of authority develops almost inevitably.

It happened to Reeves, too. In fact, Shanahan chafed under Reeves' omnipotence as much as anyone chafed under his.

"Power tends to corrupt, and absolute power corrupts absolutely," Lord Acton wrote more than a century ago. Often, despite the best of intentions, the omnipotent executive becomes an autocrat, stifling dissent, sometimes inadvertently, through intimidation. The absence of competing views, in turn, becomes an impediment to the pursuit of excellence.

Shanahan's refusal to admit that his team had become defensively helpless was a reflection of this phenomenon. Were he to walk into the current Broncos situation with no previous experience here, it's my opinion that Shanahan would replace almost everything he found on the defensive side of the ball in short order. But because everything on the defensive side of the ball, like everything else in the organization, is a result of Shanahan's own design, he had too much pride of authorship to do what needed to be done.

Sometimes, as Bowlen suggested, an executive can simply be in a place long enough. Sometimes, the burden of past decisions becomes a prison that prevents the clarity of thought a fresh perspective can bring.

That doesn't make it any easier to find a successor as good as the original. And it doesn't change the likelihood that Shanahan's firing will one day look like a mistake.

But that won't make it so. Sometimes, the weight of the history itself is reason enough.