Centuries of peacekeeping has taught that one of the more critical things to be done, is establishing peace and order. That often requires establishing a police force. In many parts of the world, that is a novel concept. Afghanistan has never really had a national police force. So the current attempt to create such an organization is the first real effort in that direction. It's not doing so well, but there is some progress.
The problems are many. First, there's the traditional method for handling crime; tribal and clan mediators and militias. This is very improvised. The tribal and clan structure still means a lot in Afghanistan, because that's all people have been able to depend on for thousands of years. The "laws" are a combination of Sharia (Islamic law) and local traditions (which often predate Islam). The traditions, and even interpretations of Sharia, vary from tribe to tribe. Thus there is the tradition of loya jirga (great council), or multi-tribe meetings where tribal elders attempt to work out compromises. No one wants tribal warfare, although there is certainly plenty of it. This is not good, because this is one of the poorest parts of Asia. War is costly, not just in terms of people getting killed in the fighting, but in terms of lost crops, herds and dwellings. That leads to more deaths in an area where one bad crop can lead to many famine deaths. Lose your home, and you might not survive the Winter. Peace is really important in Afghanistan.
The Afghan police have learned to recognize local tribal councils, and support them. The police are out of luck if they try to fight tribal tradition. It's going to take decades, if not generations, for national laws to replace local traditions. In Europe, it took centuries. France, for example, did not achieve acceptance of a national law until the early 19th century, after several hundred years of effort. England achieved it much earlier, in 11th and 12th centuries, but only because England was newly conquered and the new Norman rulers were able to use a combination of force and finesse to suppress all (well, most) of the local (tribal) laws and customs. In terms of legal systems, Afghanistan is where Europe was over 500 years ago. Expecting to change that quickly is ignoring the lessons of history.
The Afghan police leadership has also recognized that recruiting police locally, for service in the area they come from, does not work. The tribal ties, and authority of the cops tribal and religious leaders, is too great for the average policeman to overcome. This is a real, or potential, problem everywhere. But in a tribal society, it cripples the policeman's ability to enforce the law against the powerful, or even your own extended family. It's still difficult when you move cops to another area (and tribe) after they are recruited. But at least then, you take a lot of pressure off the police when they have to go up against some local big shot.
A big problem with training police was the fact that most Afghans are illiterate. This greatly reduced the recruiting pool. There were also health problems. Many Afghans have physical conditions that would be considered disabilities in the West, but in Afghanistan are just considered bad luck (or "God's will"), and you get on with your life despite it. Western trainers also had to learn what their recruits were capable of, and adopt Western training methods to Afghan realities. This was something that U.S. Army Special Forces trainers had learned over decades of training police and military personnel the world over. But over the last seven years, there's been a lot of exchanging of experience and tips between trainers, and the creation of training methods tailored to Afghan realities.
The result has been that more police are staying with the job. Police serve on 2-3 year contracts, and 80-90 percent are renewing those contracts. The AWOL (Absent Without Leave, or leaving the job before their contracts are up) rate is 5-10 percent. This is less than half what it was a few years ago. All this in spite of the fact that the drug gangs and Taliban pay their gunmen 2-3 times what a policeman makes. What makes a big difference is that the police have a much lower casualty rate, they have the powerful foreign troops on their side, and the police stand for something more Afghans believe in (no drugs or religious dictatorship.)
The U.S. has advocated forming tribal self-defense militias, under the supervision of police commanders. Local tribal volunteers would be given police uniforms (clearly marked as tribal militia), additional weapons, radios and some training. This would be done in areas where the local tribe is known to be hostile to the Taliban and drug gangs (some tribes are, some aren't). The militias would be trained to call the police and army if there is a threat, or attack, and defend themselves until help arrives. The tribes know the police have the foreign troops and aircraft on call. All Afghans are in awe, and fear, of the smart bombs. This is a big deal, and a compelling reason for many tribal leaders to side with the government. The militias would supplement the 80,000 (soon to be 97,000) national police, mainly in the south where the Taliban and drug gangs are at war with anyone who disagrees with them, or gets in the way of heroin production and smuggling.