Even the new policy of sending more troops to Afghanistan won't change the basic set-up: a weak government that can't dislodge the Taleban. But maybe it's the rival terrorist groups, not the Taleban, that should be the target of US policy in Kabul.
It is easy to blame Mr Donald Trump for everything that goes wrong in America these days, and often that is exactly the right thing to do. That is because Mr Trump's presidency is, to a quite unprecedented degree, all about the President himself.
Most of the time, he is a one-man government, utterly ignoring or wilfully defying Washington's - and even his own White House's - vast machinery of policy analysis and advice. He says or does just exactly what he feels like saying and doing -or tweeting - at any given moment. And when it goes wrong, as it so often does, he alone should take the blame.
But on some issues, Mr Trump does listen to his advisers, and, by far, the most notable of these so far is Afghanistan.
He admitted this himself when he stood up last week behind the autocue and read the speech prepared for him, announcing his administration's policy on this long and painful war.
There were, of course, some trademark Trump bombastic flourishes, but the policy he set out was quite plainly not his own. It was written for him by the generals who surround him, and the wider US military leadership from which they spring. They should take a big share of the blame for its faults.
Those faults go very deep. They spring from a fundamental mismatch between America's aim in Afghanistan and its power to achieve that aim.
This mismatch has been there from the start when, in the months after 9/11 - the Sept 11, 2001 terror attacks - America helped to topple the Taleban government in Kabul. It has never gone away, and it has doomed America's efforts there ever since. Nonetheless, it seems that America's military leaders still have trouble seeing it.
To see it more clearly, we need to understand America's ultimate or primary aim in Afghanistan. It has not changed since 2001.
It is not, and never has been, to rebuild the Afghan state or to transform Afghan society. It is to prevent Afghanistan again becoming a safe haven and training ground for terrorists who could attack America.
But even so, they have always been drawn into nation-building, because that has always emerged as an essential means to achieving their primary aim.
Here is why: The terrorist groups that America fears, like Al-Qaeda and the Islamic State in Iraq and Syria, are not primarily Afghan. They recruit from all over the world. Afghanistan can just offer them a base - as it did when the Taleban ruled in Kabul before 9/11. So the Taleban are not the real enemy. But to stop the real enemy finding refuge in Afghanistan again, so the logic goes, America has to stop the Taleban from taking control of the country again.
To do that, it must defeat the insurgency which the Taleban has been waging since its defeat in 2001. But the iron logic of counter-insurgency is that such defeats are never inflicted on the battlefield. They must be achieved by winning over the loyalty of the people to the government in power.
If that government, and the state it represents, cannot win the hearts and minds of the people they purport to govern, the insurgents will eventually win.
And if the incumbent government - like successive Afghan governments ever since 2001 - prove incapable of winning that contest on its own merits, then outside supporters must try to build them up. Hence they get drawn into nation-building, as the United States and its allies did in Afghanistan.
To this end, their troop numbers climbed to over 130,000, including 90,000 Americans, in 2010-2012, backed by billions in aid.
It eventually became clear that despite this huge commitment, the nation-building was not working.
As troop numbers fell again, it was replaced by a new idea. This was to focus on training Afghanistan's own security forces, so that they could contain the Taleban, and give the government in Kabul a chance to build popular support.
But this idea too had very little chance of success, for two reasons.
First, it overestimated the effectiveness of Western training in turning Afghanistan's ramshackle army and police into effective forces.
Second, it overlooked the essential fact that even the best forces cannot defeat an insurgency when the government they serve is so weak. So this approach too cannot work without nation-building, and nation-building does not work.
Here then is Washington's essential problem in Afghanistan: It remains fixated on the idea that America's primary goal of denying the country to terrorists like Al-Qaeda means the Taleban insurgency must be contained.
But that cannot be done while the government in Kabul is so weak, and the nation-building needed to strengthen it proves impossible to achieve.
Nothing Mr Trump announced last week will do anything to fix this. The 4,000 extra troops he reportedly plans to send will make no decisive difference to the capacity of the Afghan forces to defeat or even contain the Taleban.
The tough talk on Pakistan will do nothing effective to cut Pakistan's support for the Taleban. And the muted commitment to help strengthen the Afghan government and fight corruption will do nothing to help Kabul build support among the Afghan people.
The reality then is that America still has no credible way to contain the Taleban at a cost it is willing to bear. So maybe it is time to think again. The first step is to remember that the Taleban, for all their faults, are not America's prime concern in Afghanistan. The real problem - as Mr Trump himself made clear - remains terrorists who might threaten America.
So America needs a new and very different strategy that should focus on them more directly. The fact that the strategy Mr Trump announced last week - which is really no different from Mr Barack Obama's - does not do that is mostly, if not entirely, the fault of America's generals.
They have got too used to failure.
Hugh White is professor of strategic studies at the Australian National University in Canberra.
A version of this article appeared in the print edition of The Straits Times on August 29, 2017, with the headline 'US still stuck in failure mode in Afghanistan'. Print Edition | Subscribe
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