There is growing dissension and dismay in the US armed forces about their prospects of victory in Iraq. The yellow ribbons, lapel pins and yard signs expressing solidarity with the nation's soldiers are still conspicuous around army bases across the US. But commanders and soldiers alike are conducting an increasingly anguished debate.
There are four reasons for this. First, many service people are shocked by the incontrovertible evidence that the justification offered by the Bush administration for invading Iraq -- weapons of mass destruction (WMD) and a link with international terrorism -- were false.
Second, bitter and painful fighting, notably in the showpiece assault on Fallujah, has failed to suppress insurgency.
Third, there is deep scepticism about progress in recruiting Iraqis to assume the security burden. Even General David Petraeus, the US airborne general charged with organizing Iraq's new forces, is said to be increasingly despondent.
And finally, the army and marine corps are acutely aware that they have to sustain the occupation without sufficient troops to control the country effectively.
Having begun the campaign convinced of the justice of their cause and their ability to secure victory, many members of the US military and their families now suspect that the cause may be invalid and the battle unwinnable.
Last autumn in Iraq, a senior British officer told me how impressed he was by the Americans' commitment.
"Before I came here," he said, "I doubted whether the US army possessed the moral toughness to see this thing through. I no longer feel that uncertainty. I have not met one American at any level who questions the need to be here, and to finish the job."
That assertion is no longer true. In the minds of many US soldiers looms the specter of Vietnam. In recent years, the US army has been forged into a motivated, effective tool for large-scale military operations overseas. But it has never been suited to combating insurgency. Guerrillas and suicide bombers can impose a deadly corrosion on conventional forces.
Years ago, I heard an American general's lament for what was once a formidable Cold War fighting machine. He said to me: "We went into Korea ... in 1950 with a very poor army, and came out of it in 1953 with a very good one. We went into Vietnam in 1964 with a fine army, and came out in 1975 with a terrible one."
This is the threat that some thoughtful American officers see hanging over the Iraq deployment. The US armed forces are fighting the sort of conflict that least suits their capabilities. It would be a devastating blow to the confidence painstakingly rebuilt since Vietnam if the US, having committed enormous resources and suffered painful casualties, was obliged to quit Iraq without achieving its purposes.
Yet would military failure represent decisive defeat? Might not America ultimately prevail in Iraq by means in which armed forces play no part? Consider this proposition from Edward Luttwak, the maverick American strategy guru. In a recent speech to a British audience, he suggested that the US began to win the Vietnam war the day after its envoy was humiliatingly evacuated from the roof of the Saigon embassy in April 1975.
The military conflict was lost -- but, argued Luttwak, the US began to achieve victory culturally and economically. Vietnam may still profess a commitment to communism, but in reality capitalism is taking hold at every level. American values, represented by corporatism and schools of management studies, are gaining sway over Vietnam as surely as they are every other nation possessed of education and aspirations to prosperity.