There was no sign of the exhaustion that hangs over the White House and those wrecked by Iraq on Mr Obama's face.
Toll of war will wear down Obama's hope
Wars have a bad habit of making people grow old fast. Those who are not killed or injured usually get chewed up in some other way. It happens to the soldiers who leave their homes as young men and whose minds never return, the insurgents who forget about the cause they are meant to be fighting for, and the civilians who watch the world around them crumble through no fault of their own. Occasionally it also happens to the very politicians who make this all possible in the first place. Vietnam aged the US presidents Lyndon Johnson and Richard Nixon and it would have done the same to John F Kennedy.
After a while, the anarchy in Iraq became etched in deep lines across the face of Tony Blair, the former British prime minister. He could not shake it off and, whatever he may claim, it ruined him. The curse weighs almost as heavily on George W Bush. When Barack Obama, the presumptive Democratic presidential nominee, visited Afghanistan last week, he arrived with the message of "Change We Can Believe In". He talked about ending a war that has cost thousands of US lives and winning another one, where the death toll is in the hundreds.
There was no sign of the exhaustion that hangs over the White House and all those people who have been wrecked by Iraq. The Democratic candidate has re-energised politics in the United States and by coming here he was trying to bring along a bit of that hope, turn attention away from Baghdad and towards Kabul. Afghanistan is the key to the "war on terror", he said. He acknowledged that the battle would be tough, but outlined why it would not end in defeat. When elected, he said, he would send about 10,000 more troops to Afghanistan, take the fight to the Taliban and al Qa'eda and, if necessary, launch attacks over the border in Pakistan.
The pictures that were later made public of him eating breakfast with the soldiers, chatting with Hamid Karzai, the president of Afghanistan, and happily mingling with a notorious provincial official clearly conveyed his optimism. In a few years, though, they might come back to haunt him. Afghanistan is an unforgiving place. The land bleeds armies dry, swallowing their money, men and willpower. Hope does not last very long in this part of the world and Mr Obama's plans go against the inexorable march of time. Governments collapse here and empires fall.
Maybe he would have stood a good chance in 2001, when the US-led invasion had widespread support among a local population sick of the Taliban. Extra troops could have helped stop the militants from regrouping and without Iraq the international community might not have forgotten the promises it made to Afghans. That small window of opportunity has surely now been closed. A victory for Mr Obama or John McCain, his Republican rival, will result in an escalation of the war.
Both men believe force is the answer and they are almost certainly wrong. Troop numbers have increased markedly in Afghanistan over the past 18 months, yet security is worse than ever. Soldiers are being killed at an alarming rate and from Kandahar to Kabul the occupation is compared unfavourably with life under the Soviet Union. In the north, the murmurings of jihad are getting louder. Mr Obama's pledge to rout the insurgents means he risks further alienating the largest section of Afghan society: the Pashtuns. Mainly inhabiting the south and east of the country, they have borne the brunt of this conflict and their natural sympathy for the Taliban is already turning into active rebellion.
Concerted attacks on Pakistan's tribal areas will have the same effect, legitimising the resistance for people traditionally hostile to outside interference. More force means more air strikes like the one that killed about 50 civilians at a wedding in Nangarhar recently. It also means the Taliban will respond in kind, with suicide bombings, improvised explosive devices, ambushes and kidnappings. Fighting will spread to areas that have been peaceful.
The problem the next US president has is that his government will be viewed with deep suspicion and hatred here even before he has taken office. Washington abandoned Afghanistan after the Soviets left, then promised to make up for the mistake. But today it allows warlords reviled by Afghans to hold positions in Mr Karzai's corrupt regime and it cannot bring security. Mr Obama offers nothing new in a country sadly accustomed to bloodshed. Indeed, history may have already delivered its verdict on his plans. Look again in a couple of years and you will see the outcome in his eyes.