Law Enforcement Officers' Military Service Act - Allows a law enforcement officer who is involuntarily called or ordered to active duty or involuntarily retained on active duty for any period beginning on or after September 11, 2001, to receive credit for such period of active duty (as military service) under the Federal Employees Retirement System. Waives the requirement that such individuals deposit a specified percentage of basic pay received during such periods of military service to receive such credit.