“American military commanders have long recognized that the insurgency benefits from a pernicious force stalking Afghan national troops, one that attacks from inside the ranks. That enemy is corruption — in the form of shakedowns at traffic stops, other types of petty bribery, phony surcharges and ‘ghost’ workers whose salaries are pocketed outright by supervisors.”
Source: Corruption enemy No. 1 for Afghan police | UTSanDiego.com