To his presumed dismay, and certainly to the US military’s detriment, General David Petraeus has become a polarising figure in Washington.

Democrats are furious at what they regard as a politically inspired whitewash by the commander of US forces in Iraq designed to please his masters in the White House. Today, they used the opportunity of his long-awaited testimony to two House of Representatives committees to attack the General’s broadly upbeat assessment of the progress of the surge and his plea to allow the military to continue the fight at least until next summer.

Though they carefully stopped short of outright hostility towards the solemn man with the four stars on his epaulettes, Democrats lined up to express deep scepticism at Gen Petraeus’ claims of significant progress.

"The administration has sent you here today to convince the members of these two committees and the Congress that victory is at hand. With all due respect, I don't buy it, “ said Tom Lantos, chairman of the House Foreign Affairs committee.

General Petraeus: The Times interview

'What sustains you is the Iraqis who are incurring enormous risk to try to achieve the vision of a new nation in an ancient land'

BACKGROUND

• Comment: General Petraeus polarises Washington

• Q&A: General Petraeus and the surge

• Petraeus dresses right for critical moment

• America can’t just walk away, US general insists

• New US general will copy British 'softly-softly' style

Other war critics went further. Protestors in the House hearing room shouted “war criminals” at the general and Ryan Crocker, the US ambassador to Iraq, who testified with him. Uglier in its way was a characteristically unpleasant attack advertisement in the New York Times taken out by the left-wing antiwar group MoveOn.org. It accused the general of lying about the progress of the war and mocked him as “General Betray Us.”

It is odd that Gen Petraeus should be getting such flak.

It is odd first of all, because it is not what Democrats were saying when they agreed eight months ago to the appointment of the general as commander in Iraq. Back then Democrats lined up to associate themselves with someone routinely praised as a war hero for his earlier contributions to the war in Iraq. He was confirmed by the US Senate without a single dissenting vote. Democrats knew at that point that the general favoured the surge; indeed he was one of the architects of the strategy. Now they don’t like his advocacy of it or his hones assessment to judge his progress.

It’s odd, secondly, because the surge is indeed showing signs of real progress, as Gen Petraeus explained at the hearing. This was no triumphalist performance. He was sober and restrained and expressed great caution about the long-term prospects. But he also laid out in simple, statistical detail how he has kept up his end of the bargain by helping achieve significant improvements in security.

But it’s odd most of all, and indeed dangerously curious, because in the end it is of course right that military leaders should be committed to the military objectives they have been tasked to complete.

Gen Petraeus has a mission to execute. He is in the process of executing it. He is not there to critique the broader strategy nor is he likely to insist to members of congress that his men and women should be free to carry on with a failed mission.

Democrats agreed to the process by which the general himself would report to congress on the progress of the surge. Now they seem to want to discredit that process.

The really dangerous aspect to all of this is that one day Democrats really will be in charge of the US armed forces again. They of all people should be aware of the risks to the democratic process in politicising the military leadership.

The loss of confidence in the independence of the US military leadership in Vietnam was one of the most damaging long-term effects of that war. Politicians on both aides will be the losers if that miserable experience is repeated.

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