The audacious attacks carried out by the Taliban in the heart of Kabul have once again exposed the increasingly glaring discrepancy between the official version of the Afghan war and the actual situation on the ground.
For the last year, US and British military commanders have painted an upbeat picture of the war in which their forces are "gaining momentum", "disrupting Taliban activity", "degrading their capabilities" or "denying them control of population areas."
Only last month, during David Cameron's state visit to Washington, Barack Obama declared
"Our forces are making very real progress: dismantling al-Qaeda; breaking the Taliban's momentum; and training Afghan forces so that they can take the lead and our troops can come home."
Now the Taliban have carried out the most serious assault in Kabul in 11 years, simultaneously attacking embassies, a supermarket, a hotel and the Afghan parliament, in addition to attacks on US bases and Afghan police stations in three other provinces.
Not surprisingly, both Afghan and NATO officials are frantically trying to spin this humiliation as a kind of success. The International Security Assistance Force (ISAF) have described them as "ineffective". ISAF's commander, U.S. Marine Gen. John Allen has praised the response of Afghan security forces to the attacks and suggested, somewhat illogically, that yesterday's choice of targets, "speaks volumes about where we are in this campaign" to create a "sovereign Afghanistan responsive to its people."
Afzal Aman, the Chief of Operations from the Afghan Defence Ministry, has taken the same line, arguing that "In only a short time we managed to cut short their devilish plans and all 32 insurgents were killed. They carried suicide vests, but managed to do nothing except be killed."
In fact these attacks managed to achieve a great deal more than that. Politically they demonstrated that the Taliban has the organising capacity to plan and carry out attacks in the Afghan capital, and that neither NATO or the Afghan security forces are able to prevent them.
In doing so, they have exposed talk of "momentum" and "progress" as the hollow and essentially meaningless propaganda that it is, and they have called into question the prospect of a managed withdrawal of NATO troops in which security is handed over to the Afghan security forces.
In June last year, US Defense Secretary Robert Gates tried to talk down prospects of winning or losing in relation to Afghanistan, arguing
"We have not had a declared victory in a war, with the possible exception of the first Gulf War, since World War II. It is the phenomenon of modern conflict...The key is, are our interests protected? Is the security of the United States protected? Are the American people safer at the end because of the sacrifice of these soldiers have made? That's the real question."
Gates was only partly right. In guerilla wars of the type that the Taliban has been waging in Afghanistan, victory and defeat is not measured in strictly military terms. Guerillas/insurgents 'win' by not losing, because they are able to endure, grow and reconstitute themselves again and again until their enemies can no longer find the resources or political will to stop them.
As Ho Chi Minh once observed, "You will kill 10 of our men, and we will kill one of yours, and in the end it will be you who tire of it." A similar dynamic applies in Afghanistan. For more than a decade, NATO has been fighting a war whose objectives are vague, illusory, and often fantastic.
In January this year, the whistleblower Lieutenant Colonel Daniel Davis leaked a searing report to Rolling Stone magazine, which radically contradicted virtually every claim that has been made by his own government and military commanders for the last two years.
A former serving officer in Afghanistan, Davis accused US military leaders of deceiving the US public about a war which he insisted was characterised by "the absence of success at virtually every level." Davis' conclusions have been largely ignored by the US military and political establishment, that cannot or will not acknowledge its inability to achieve its aims.
Vietnam was marked by a similar gulf between official rhetoric and reality, in which propaganda, lies and official groupthink combined to present a fantasy version of the war and offered body counts and vague talk of 'progress' as substitutes for victory.
In the end, as Ho Chi Minh predicted, the American public did tire of it and withdrew. A similar outcome will almost certainly occur in Afghanistan, but the danger is that it will come too late, and the withdrawal of foreign troops may pave the way for a return to the Afghan civil wars and warlordism of the 1990s.
To prevent this outcome, real open-ended negotiations between all contending political forces in Afghanistan, both national and international, are essential, and sooner rather than later.
Such a process requires a different kind of 'momentum' towards political rather than military solutions. But it also requires politicians with the courage to face up to reality and acknowledge failure, and for the time being at least, such leaders are nowhere in sight.
Follow Matt Carr on Twitter: www.twitter.com/MattCarr2