There are numerous reports of Afghan National Police (ANP) corruption so the Afgan cops have an ulterior motive for wanting to go out on their own; i.e., they want to be able to shake down villagers, or even take bribes from the enemy, without witnesses or interference. I believe their US trainers do not really trust the ANP, or the Afghan National Army (ANA), to be very effective even without corruption. They know that many of their trainees are there only for the pay and may avoid battle with the enemy given the chance. They know that some are actually Taliban spies.
Mohammad Pashtun, the chief of the criminal investigation unit in southern Kandahar province, the Taliban's heartland, said that the money would be better off going to Afghan forces.
"Increasing international troops is not useful," he said. "For the expense of one American soldier, we can pay for 15 Afghan soldiers or police."
The top U.S. and NATO spokesman in Afghanistan, Adm. Gregory Smith, agreed that Afghan forces would be key to defeating the Taliban. But he added that the "major way forward" was to partner international troops with Afghan ones on a day-to-day basis, and not simply for the West to train Afghan forces and send them out on their own.
There is a valuable report at Asia Times on the status of the Afghan forces: US wins minds, Afghan hearts are lost By Ann Jones.
In my estimation the old search and destroy approach was rightly abandoned by the generals as counterproductive. However the new more restrained counterinsurgency (COIN) strategy is not even close to being sufficiently better to "win" the war in Afghanistan, (whatever that means). It has uneven support among the troops. It only leads to a Viet Nam-like quagmire war and eventual humiliating withdraw ordered by a successor US President who will have campaigned on a pledge to bring the troops home. Neither can a campaign limited to missile and air strikes and special forces raids do much beyond providing some political cover for withdraw of stationed land forces.
The fact is that the main defenses against future terror strikes at home are what can be done within our own borders and, along with that, what can be done with diplomacy and foreign policy to discredit terrorist organizations abroad and minimize their support. Military force is, at its best. almost useless against organized terror much as it is usually an ineffective and inappropriate tool for use against organized crime. At much less than its best, military force is counterproductive and that it how it tends to be applied even when the strategists and military historians and theorists know better.