Donald Rumsfeld is one of this administration's great survivors. But now, in the wake of the evidence of the mistreatment of Iraqi prisoners, his job could be on the line.
He has already been admonished by President George Bush.
Is Mr Rumsfeld a plus or a liability to the Bush administration?
His apparent failure to relay the gravity of the charges of abuse, together with the Pentagon's failure to get a grip on the detention system once such mistreatment was made clear, has caused President Bush fundamental embarrassment.
It has only aggravated the mistrust with which the US Army is viewed in Iraq and heightened suspicion about the values that America is claiming to be bringing to the country.
It worsens Washington's wider standing in the Arab world. And it probably does little to recommend the US project in Iraq to America's friends and allies around the world.
'On the skids'
The sometimes ebullient, sometimes cantankerous Donald Rumsfeld stands at the epicentre of the problem.
He is a genuine political veteran. Indeed, his political longevity is remarkable. He ranks as both the youngest ever and the oldest ever Defence Secretary in US history.
He first served as Defence Secretary in the Ford Administration between 1975 and 1977.
But he is probably also the most controversial.
Mr Rumsfeld has been on the skids before. Prior to the 9/11 attacks, his great project of transforming the US military into a lighter, more agile force had run into the sand.
He had offended powerful groups on Capitol Hill, not to mention much of the military top brass. The newspapers began to speculate about his successor.
'Mistakes his own'
But then came 9/11 and the dramatically successful campaign in Afghanistan. Mr Rumsfeld's stock rose.
Mr Rumsfeld is under fire due to the row over US abuses in Iraq (AP/Courtesy The New Yorker)
The war in Iraq - despite some bumpy moments - appeared to be another success for the Rumsfeld doctrine of deploying lighter, less numerous, but technologically highly capable forces.
He confounded his critics. US troops were in the Iraqi capital Baghdad in less than a month.
But since then, things have gone badly wrong. And many of the mistakes seem to be of Mr Rumsfeld's making.
There were too few troops in Iraq to provide security for the country once Saddam Hussein's regime was toppled.
The disbanding of the Iraqi army looks in retrospect to have been a serious mistake, removing the only authentic Iraqi force that might have been able to move quickly to restore order.
Mr Rumsfeld's Pentagon has largely had stewardship over Iraq. And if things have gone badly there, then critics say, it is hard to place the blame elsewhere.
'Preparing for interrogation'
The problem of the mistreatment of prisoners is also ultimately linked to Mr Rumsfeld.
Of course he does not condone such treatment and is probably as appalled as anyone else by the photographs that have been so widely published.
But human rights groups have long argued that the problems in Iraqi prisons - and in those in Afghanistan as well for that matter - amount to "systemic" abuse.
It is not that every prisoner is tortured or mistreated. But many of the rules and regulations governing the treatment of detainees have been suspended or have been deemed to be inapplicable - largely at Mr Rumsfeld's behest.
So the Geneva Conventions have not been applied; the concerns of the ICRC have been ignored; and even basic military procedures - the principle that military police guards should not be involved in what is euphemistically described as "preparing prisoners for interrogation" - has been ignored.
So where does this all leave Mr Rumsfeld? Mr Bush is still publicly backing his defence secretary.
His fate could depend upon attitudes on Capitol Hill.
Prominent Democrats have called for Mr Rumsfeld's resignation, but so far senior Republicans on Capitol Hill have held back, waiting to see what kind of performance the Defence Secretary puts up when he appears before two influential Congresional committees on Friday.
So is Mr Rumsfeld a plus for this administration or a liability?
He certainly has his admirers as well as his enemies. Handling the Iraq dossier requires someone of remarkable strength and resilience.
And there is no doubt that Mr Rumsfeld has ample quantities of both.