To amend title 10, United States Code, to authorize the Secretary of Defense to assign members of the Armed Forces, under certain circumstances and subject to certain conditions, to assist the Immigration and Naturalization Service and the United States Customs Service in the performance of border protection functions.

Authorizes the Secretary of Defense to assign military personnel to assist: (1) the Immigration and Naturalization Service in preventing the entry into the United States of terrorists, drug traffickers, and illegal aliens; and (2) the U.S. Customs Service in the inspection of cargo, vehicles, and aircraft at points of entry into the United States.

Requires: (1) the establishment of an appropriate training program for such personnel; and (2) a civilian law enforcement officer from the appropriate agency to accompany any member performing duties at a border location.

Prohibits any such assignment from being made or continued after September 30, 2003.