Stop Militarizing Law Enforcement Act This bill revises the authority of the Department of Defense (DOD) to transfer excess personal property to federal and state law enforcement agencies. DOD's authority to transfer property for counter-drug activities is eliminated. DOD property recipients must: (1) provide DOD with a description of intended use; and (2) certify that they have appropriate personnel, technical capacity, and training and will return any surplus DOD property. Non-federal recipients must certify that they have notified their local community of requests for DOD property. The following transfers are prohibited: controlled firearms, ammunition, grenades, and explosives; controlled vehicles, certain trucks, and other highly mobile or mine-resistant ambush-protected vehicles; armored or weaponized drones; controlled aircraft that are combat configured or combat coded, or that have no established commercial flight application; silencers; long range acoustic devices; and items in the Federal Supply Class of banned items. Transfers conditioned upon the agency demonstrating the use of any small arms or ammunitions are prohibited. Transfers of previously transferred DOD property from one federal or state agency to another such agency are prohibited. DOD may waive transfer prohibitions for certain trucks and vehicles (other than mine-resistant ambush-protected vehicles) if necessary for disasters, rescues, or other purposes where life and public safety are at risk. DOD shall require as a condition of any property transfer that the recipient agency shall return the property if the agency is: (1) investigated by the Department of Justice for any violation of civil liberties, or (2) otherwise found to have engaged in widespread abuses of civil liberties. Obligations or expenditures of appropriations to carry out DOD's property transfer program are prohibited unless specified conditions are met. Federal or state agencies that receive controlled property may not take ownership of such property.