Not for the first time, realities on the ground have exposed the frailty of America's plans. Following President Barack Obama's "surge" of extra US troops into Afghanistan, this was meant to be a moment when violence was in decline, allowing the West to make a withdrawal by 2014.
At the same time, the Taliban was supposed to be coming to the negotiating table, where its leaders would be the weaker party in a settlement designed to resolve the country's troubles.
The Taliban has shown that it can still execute "spectacular" attacks on multiple targets inside Kabul itself. The first lesson is the simplest: after facing the mightiest military machine in history for more than a decade, the Taliban remains an immensely capable force.
To strike seven targets in a city protected by a "ring of steel" is a big undertaking. True, the Taliban has shown its mettle in Kabul before, notably last year when it attacked the British Council and the US Embassy. Yesterday's strikes were far more ambitious.
Ryan Crocker, the US Ambassador, suggested that the Haqqani network, a separate extremist group allied to the Taliban, might have been responsible. But this matters very little. The point is that the extremists were able to infiltrate large numbers of fighters and weapons into a tightly-guarded city.
They were able to prepare their operation, probably over a period of months, and did this apparently with operational security, without any intelligence agency knowing of their intentions.
The second lesson is the converse: if the Taliban is stronger than some thought, Afghanistan's own security forces are weaker.
The Afghan National Army and police have primary responsibility for Kabul's security, a state of affairs that is supposed to be replicated across the entire country by the end of 2014. These attacks raise serious questions over their fitness for the job.
Local security forces are the West's exit ticket from Afghanistan: foreign troops can only leave when the country's own soldiers and police are fit to take over. America and Britain have already announced that their combat units will go by the end of 2014. But will they be able to leave if Afghan forces cannot stop attacks like yesterday's?
That raises the starkest question of all: if real negotiations with the Taliban do commence, who will have the bargaining power? It appears that the West will not be dealing with a weakened force desperate for a respite. In fact, the Taliban have strengthened their ability to influence Afghanistan's political future. (© Daily Telegraph, London)