Preservation of the United States Military Chain of Command Act of 1999

Preservation of the United States Military Chain of Command Act of 1999 - Prohibits U.S. armed forces from being placed under the command or control of any foreign national for participation in a United Nations (UN) operation: (1) unless the President certifies to the appropriate congressional committees that such forces will not be involved in combat; or (2) if the operation is authorized under chapter VII of the UN Charter. Prohibits U.S. armed forces from participating in conjunction with or in support of a UN operation unless specified requirements are met. Requires the Secretary of Defense to report biannually to the appropriate congressional committees on the service units of U.S. armed forces under the operational or tactical control of a foreign national, whether in an established regional alliance like the North Atlantic Treaty Organization or in an ad hoc military coalition.