Rupert Cornwell: Burden of sending men to their deaths is starting to show

George Bush, famously, followed his gut instincts – and took the US into a misbegotten war in Iraq. His successor, on the other hand, prefers to take his time and think a problem through. Alas, it would seem that the more Barack Obama thinks about Afghanistan, the more intractable the problem becomes.

Barely seven months ago, citing exactly the same factors as now – a growing insurgency, a rising US death toll, corrupt local government – the President announced a new Afghan strategy, including the commitment of more troops, money and civilian assistance, aimed at eliminating the threat from al-Qa'ida.

That remains the objective. And only a few weeks ago, it looked as if Mr Obama would go along with the request of General Stanley McChrystal, the US commander in Afghanistan, for a force increase of 40,000. But instead a final decision has again been put off, and the President may be leaning towards a smaller boost. So what changed?

One ingredient in the debate of course is the reported opposition of former general Karl Eikenberry, America's ambassador in Kabul, to an immediate troop increase. His misgivings stem apparently from doubts about the credibility of President Karzai, and the lack of an exit strategy. The two men's stances give rise to a rare scene: two of the most senior US officials in Afghanistan, in open disagreement over what should be done.

But Mr Eikenberry's objections are nothing new. The Karzai government's shortcomings, and the lack of clarity about the US mission in Afghanistan, were plain to Mr Obama back in March. What has changed is that he has realised what it really means to be commander-in-chief in time of war.

Healthcare reform and coping with economic recession are huge challenges. But they pale beside the direct responsibility of sending young men to fight and die in a war that may be unwinnable. That burden was visible on Mr Obama's face when he visited Dover Air Force Base to see the coffins of dead soldiers returning home, when he visited the wounded at Walter Reed hospital, and when he lingered this week in Arlington Cemetery at the graves of soldiers killed in Iraq and Afghanistan.

Inevitably, the delay in a decision has led to accusations of "dithering" and presidential weakness (even though a little more "dithering" by Mr Bush in 2003 might have spared the US thousands of lives).

The parallel though is not only with Iraq. Haunting America are memories of an earlier conflict as unwinnable as, and even more unpopular than, Afghanistan: the Vietnam War which destroyed Lyndon Johnson, another Democratic president with a massive ambitious domestic agenda.

Mr Obama is learning the real importance of the question posed by a decorated young veteran named John Kerry back in 1971, to members of the Senate Committee on Foreign Relations of which he now happens to be chairman. "How do you ask a man to be the last man to die for a mistake?"