Kabul is a tightly controlled city. No one drives into the Afghan capital without passing through inspections and roadblocks. The city center has a further security cordon.

Therefore, the Afghans who walked Tuesday along the sidewalks of Darulaman Road had a fair expectation of being safe from bombing outrages. Likewise, the NATO convoy that drove down that street probably imagined they were mostly running a reassuring publicity exercise.
Then a Taleban suicide bomber in a vehicle packed with almost three quarters of a ton of explosives drove into the convoy. Twelve Afghans died, together with six NATO soldiers, one a Canadian and the rest American troops, whose commander in chief Barack Obama had so warmly shaken the hand of Afghan President Hamid Karzai only last week.
What should be made of this horror in which, for the first time in recent months, NATO casualties were almost as heavy as those of defenseless and innocent civilian? For a start, something is clearly seriously wrong with the security cordons established around and within the Afghan capital. Either they are fundamentally ineffective, or else the personnel manning them have been infiltrated by the Taleban. Either way this new deadly attack plays into the hands of the Afghan government and their NATO allies.
At the base of every insurgency is the simple matter of statistics. Every successful terrorist attack ought to generate a counterreaction, whereby the failures that allowed the assault to succeed are identified and remedied. The most particular failure that will be identified in the wake of Tuesday’s murderous attack in Darulaman Road is who it was, through incompetence or collusion, that failed to stop the car bomber or the explosives entering the Kabul security cordon. That security force member does not have very far to run. There are timed video records of the vehicles that pass through every checkpoint. Once the car bomber’s car or truck is identified, it will be clear who was on duty at whichever checkpoint that the vehicle, with or without its deadly cargo, passed through.
There may be a range of reasonable explanations for why the security men involved failed to suspect or spot a terrorist movement. Reasonable or unreasonable, the Afghan authorities, no doubt assisted by NATO forces, ought quickly to discover if there has been a breakdown in security and that being the case, who is likely to have been responsible. On the face of it, therefore, it should be a simple matter to isolate and question any suspects and if they are guilty, perhaps obtain leads to the rest of their network.
The point is that the slaying of five U.S. soldiers, which will have a disproportionate impact on the U.S. public, who prefer their violence to come in video games, is going to have only a limited effect on the Afghan government and its NATO military backers. Upon the Taleban, however, the effect of Tuesday’s bombing is clear. One more bigoted dupe became no longer available for further fanatical acts and the authorities will now close freshly exposed security loopholes