Underpaid, under-equipped and under-trained, Afghanistan's 93,000-member police force is the weak link in an ambitious security strategy to hand over defense of the country to Afghans so American and other foreign troops can go home.A strong, unified national police force has long eluded Afghanistan, a country torn by occupation and warfare for hundreds of years. But with the West now attempting to help turn the country from a failed state into at least a functioning one, the police will play a crucial role in making cities safe places to live.