Nobody is bigger than the boss - not even Rooney
From Paul McGrath and Norman Whiteside in the early days, then, as his authority was cemented, to Paul Ince, David Beckham, Jaap Stam, Roy Keane and Carlos Tevez, Alex Ferguson has always been prepared to ship out good players, even great ones, who challenge him either directly or through the way they live.
Wayne Rooney, it appears, may be about to find that he is as dispensable as the others.
There are times when this refusal to countenance dissent has weakened the team in the short term, such as when Stam was forced out, but even at 70 years of age Ferguson takes the long view.
Rooney would be very difficult to replace, but it is harder to control a dressing-room when some of its members believe themselves more important than the boss.
Ferguson has said that a manager can never lose an argument, suggesting he has not, but this is only partly true. Players have more power now, and he was unable to hold on to Cristiano Ronaldo and Gerard Pique.
He has also been prepared to compromise when he needs a player. As Keane recently revealed, he and Ferguson had many disputes when the Corkman was in his prime.
Ferguson always found a way to make peace, to accommodate his warrior captain. Until, that is, Keane's powers began to wane. Then Keane was shown the door. As he said last month, "the difference then was that I was 34."
Rooney is only 26, and still growing as a player, but his performances lack the reliability of Keane. In the last couple of years Rooney's form has either been red hot, or ice cold.
While some players play to par regardless of what maelstrom may be enveloping them, extraneous factors seem to weigh Rooney down.
When that happens his body language betrays a lack of desire and he seems to draw within himself before lashing out, as with England in Montenegro, in apparent frustration.
The split between Ferguson and Rooney is understood to date back to the infamous transfer request just over a year ago.
Then Ferguson gave in, swallowing his pride to welcome Rooney back into a dressing-room the quality of whose occupants Rooney had questioned.
As when he settled with Keane, Ferguson had considered the bigger picture and he seemed to be rewarded.
In the second half of last season Rooney scored nine goals in 13 Premier League starts as United regained the title. All seemed well.
Rooney began this campaign scoring at a rate superior to a goal per game, but then came the arrest of his father and uncle for alleged involvement in a match-fixing scheme. The following day he played against Montenegro, scored, but was then dismissed.
Since then he has scored five goals in 15 games. In itself that would not be a problem, not least because he played on several occasions in midfield because of United's lack of alternatives, and did well there.
What appears to have infuriated Ferguson is the Christmas night out with Jonny Evans and Darron Gibson, Rooney's allegedly dishevelled and uninterested appearance at training the following day, and the subsequent sulky performance when recalled at Newcastle.
Whilst Ferguson has shown in the past he is prepared to give way when dealing with star players -- his initial reaction to Eric Cantona's lunge into the crowd at Selhurst Park was to sack him -- there is a line he, and any other manager, must draw.
When a senior player becomes mutinous he has to be moved on. Otherwise he will become the focus of a negative clique in the dressing-room, and a bad example on the training ground.
The latter aspect is crucial at United. A hunger for success is not easy to sustain -- many players, inevitably, become sated. For years Ferguson has succeeded in driving United on to title after title and one of the means by which he has done so is through a training-ground culture in which senior players set the lead.
Keane, Gary Neville, Paul Scholes and Ryan Giggs were all outstanding trainers -- as were Cantona and Beckham. New players, and youth players, join United, see how hard the stars work, and follow suit. Rooney is now one of the senior pros.
At a time when United's young players have been accused of being complacent -- notably by Keane after the debacle at Basel -- Ferguson cannot allow a diminution of commitment.
That Ferguson felt he had to discipline Evans and Gibson too will not have helped Rooney's cause.
It may be that Ferguson has decided Rooney has to go because of his stature, not despite it. (© Independent News Service)