KABUL — 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.