A British diplomat in Kabul, reached by phone in the middle of yesterday's mayhem, was exasperated. "I really don't know why they are doing this – we'll be out of here in two years' time, all they have to do is wait." The answer, not completely glib, is that the insurgents carried out the attack because they could.
The Isaf (International Security Assistance Force) gave a statement, while fighting was still going on, that the bombings and shooting had been "ineffective". Viewed through a narrow military prism, this may be true. By late afternoon, according to the authorities at least, 14 militants had been killed with no loss of government or civilian lives.
But the assaults were not entirely symbolic or aimed at a psychological victory, although both these aims were achieved. One target, apparently, was Ahmed Karim Khalili, a vice-president and a Hazar from the north of the country. Several figures from the old Northern Alliance, the Taliban's enemy in the bitter civil war, have been eliminated.
The ISI-backed Haqqani network, or whoever was responsible for the attack, know there could be another civil war and may be preparing for it. New battle lines are being drawn up; yesterday saw Russian troops protecting their embassy as it came under attack for the first time since Russia's doomed invasion in 1979. Old Mujahideen commanders who fought against the Soviets, and who are now MPs, picked up guns to fight back against the insurgents.
The combatants, it seems, cannot wait for the Western forces to leave. Meanwhile, Nato faces a difficult period. Yesterday's violence came as defence and foreign ministers prepare to meet in Brussels next week to discuss Afghanistan and work out a blueprint for the end of Nato's mission in the country.
The logical course would be to listen to military commanders and leave the bulk of the forces on the ground, to give Afghan forces the utmost time to get ready. But the political expediency at home means that this will probably not happen.