Reading Room Document

Presidential Authority to Permit Incursion Into Communist Sanctuaries in the Cambodia-Vietnam Border Area

Congress has clearly affirmed the President's authority to take all necessary measures to protect U.S. troops in Southeast Asia. Having determined that the incursion into the Cambodia-Vietnam border area is such a necessary measure, the President has clear authority to order it. The President's action with respect to the Cambodian border area, limited in time and in geography, is consistent with the purposes which the Executive and the Congress have pursued since 1964. Whatever theoretical arguments might be raised with respect to the authority of the Commander in Chief to act alone had there been no congressional sanction for our involvement in Southeast Asia, there is no doubt as to the constitutionality of the action in light of the prior affirmance of Congress that the Commander in Chief take all necessary measures to protect U.S. forces in Vietnam. Having determined the necessity, the Commander in Chief has the constitutional authority to act. The OLC does not provide release dates for its opinions, so the release date listed is the date on which the opinion was authored. The original opinion is available at www.justice.gov/file/20821/download.

May 14, 1970