One of the fundamental challenges the U.S. military has never really figured out is what to do about IEDs. They've built bigger trucks, designed robot blimps, and bulldozed entire villages to deal with the homemade bombs. The race against IEDs is, in a way, an arms race—one where the defensive party (that's us!) has all of the disadvantages.
But IEDs are more than their constituent components. Right now, many IEDs are triggered by timers or even pressure plates that were buried in the road. This is because the U.S. military blankets areas with radio scramblers to prevent remote detonation. They can detect signal lasers and physical cables leading off the road to a detonator. For each measure the U.S. adopts to one-up the IEDs, the insurgents create new workarounds that are harder and harder to defeat.
At its heart, however, the scourge of IEDs is not a technological problem. We can safely assume the arms race of measure and counter-measure will continue for a long time at huge cost. The real problem of IEDs is a political and strategic one. Much like with suicide bombing, insurgents use IEDs because they are effective: they're hard to defeat, they cause a lot of damage if not a lot of death, and the psychological toll they exact on the counterinsurgents is extreme.
The Taliban pay attention to this. They know IEDs are a horrific thing to encounter: much worse than ambushes, gun fights, and snipers, because they seem so random. As a political strategy—to demonstrate the impotence of the foreign forces and to show that all the billions of dollars of gadgets they use still can't protect them—it is devastatingly effective.
ISAF, whether led by General Petraeus or not, still does not understand that the war in Afghanistan is a political war first and foremost: a war of emotions, perceptions, and messages. His tone-deaf statements to the press notwithstanding, the entirety of ISAF's messaging misses the politics of the situation unfolding in Afghanistan. As an example, here is a recent move the Taliban has made in Ghazni province:
GHAZNI CITY (PAN):
The Taliban have banned frozen chicken sales in several parts of
southern Ghazni province on the grounds that the method of slaughter is
Abdul Fatah, a vendor of frozen chickens, said that consumers no
longer bought poultry products in some districts. "Shopkeepers and
butchers who had been buying from us were told by the fighters to stop
because the method of slaughter is un-Islamic."
The frozen chickens are imported from the United States, Brazil,
China and India. The Taliban say butchers in those countries do not
follow Islamic slaughtering practices.
It's easy to laugh at this, cry for the humanity, and move on to something else. But as goofy as forbidding inexpensive imported frozen chickens might seem, this prohibition is speaking to a much deeper issue with the war. From the start of their re-emergence in 2003, the Taliban have spoken to the politics and the faith of Afghanistan: we are good Muslims, they say, and we wish to protect you from these anti-Muslim outsiders.