Donald Rumsfeld has been around for a very long time and has not changed much in the intervening 35 years. No one doubts that the US Defence Secretary, as he fights for his political life, still has those qualities in spades.

But being tough and ruthless may not be enough to save him this time, particularly when large sections of the American military establishment prefer to describe him as arrogant, stubborn, and just plain wrong.

In the past month, half a dozen former generals have called for him to quit the Pentagon for disastrously mishandling the Iraq war. Although the White House confirmed yesterday that President Bush was planning a wideranging shake-out of his team, Mr Bush interrupted his Easter break last week to give the Defence Secretary his unqualified backing. But the blizzard of criticism, which began in earnest with the publication of Cobra II, a well-sourced account of blunders made in the preparation, execution and aftermath of the 2003 invasion, shows no sign of abating.

At least two more books are being written on a similar theme, while it is said that more former generals are waiting in the wings to add their voices to the clamour for Mr Rumsfeld’s removal. The atmosphere in the Pentagon is, by all accounts, ugly.

There are some who suggest that the generals, being military men, might have been brave enough to voice their doubts before reaching retirement rather than being cowed by a septuagenarian civilian such as Mr Rumsfeld. But this, their supporters say, fails to understand the constitutional role of the military, which can only offer advice and must follow orders from the political leadership. The problem with Mr Rumsfeld, they say, is that he neither heeded their advice nor took kindly to it. General Eric Shinseki, the US Army Chief of Staff, was effectively sidelined for telling Congress in 2003 that the Iraq invasion would require several hundred thousand troops. The Defence Secretary stuck to his view that the war could be won swiftly with far fewer troops, using the latest technology. He disbanded the Iraqi military and failed to give guidance to troops about preventing looting, saying only that “stuff happens”. Then he ignored warnings of an impending crisis with insurgents. The charge sheet lengthens to describe how Mr Rumsfeld overrode decisions on the ground and demoralised troops.

Over the weekend the Pentagon hit back, releasing a memorandum that showed that Mr Rumsfeld was repeatedly consulted by the military, meeting members of the joint staffs 139 times and combat commanders 208 times since 2005.

General Richard Myers, who recently stepped down as chairman of the Joint Chiefs of Staff, said that General Shinseki might have been treated a little better, but insisted that the overall relationship between Mr Rumsfeld and the military functioned as it should.

The dispute reflects divisions that go far deeper than criticism of Mr Rumsfeld’s management skills. He entered the Pentagon determined to shift the military from a force designed for the Cold War to one suited to unpredictable threats.

The toppling of the Taleban in Afghanistan and initial success in Iraq bolstered his position. But the subsequent setbacks have given ammunition to critics who say that his “effects-based” doctrine, which relies heavily on technology and speed, is ill-equipped for the long war against terror.

()The dispute is reviving arguments about whether the invasion of Iraq was ill-conceived. Mr Bush can ill-afford to lose Mr Rumsfeld because the attacks on the Defence Secretary are a proxy for a wider assault on himself.

Mr Rumsfeld said yesterday that the calls for his resignation would pass: “The sharper the criticism comes, sometimes the sharper the defence comes from people who don’t agree with the critics.”

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