The application of the Geneva Conventions of 12 August 1949 to captives in the Vietnam War was complicated by the perplexing legal nature of that conflict. In the classic sense, the conventions presume a declared state of war between two or more sovereign states, each fielding a regular army fighting on a readily identifiable battlefront. Virtually none of these classic conditions existed in the Vietnam conflict.

The United States recognized the sovereignty of South Vietnam, as did some eighty-seven other nations. Indeed, South Vietnam is a member of several special committees of the United Nations, and would have been a member of the United Nations itself had it not been for a Soviet veto in 1957.

The United States has not accorded full diplomatic recognition to North Vietnam, as have some twenty-seven other states. However, the United States has acknowledged North Vietnam's agreement to the Geneva Conventions of 1949, and it has treated North Vietnam as a separate state in the context of Article 12 of the Geneva Prisoner of War Conventions.

Throughout the course of the war the government of North Vietnam was most reluctant to admit to any involvement in South Vietnam, constantly maintaining all of Vietnam to be one country and the Saigon government a puppet regime, beleaguered by indigenous patriots who wished to restore the country to the people. The Republic of Vietnam, while asserting its separation from North Vietnam and its existence as a sovereign state, steadfastly refused to accord to the Viet Cong any degree of legitimacy, either as a separate political entity or as an agent of Hanoi.

Neither the United States nor North Vietnam issued a declaration of war. South Vietnam declared a state of emergency in 1964 and a state of war in 1965, actions taken primarily to increase its internal powers.

The types of combat forces in the war ranged the full spectrum from the regular divisions of the United States, South Vietnam, and North Vietnam to the Regional Forces and Popular Forces of the government of South Vietnam, the Main Force and Local Force battalions of the Viet Cong, the Civilian Irregular Defense Group of South Vietnam, and the secret self-defense groups of the Viet Cong. The battlefield was nowhere and everywhere, with no identifiable front lines, and no safe rear areas. Fighting occurred over the length and breadth of South Vietnam, on the seas, into Laos and Cambodia, and in the air over North Vietnam. It involved combatants and civilians from a dozen different nations. Politically, militarily, and in terms of international law, the Vietnam conflict posed problems of deep complexity. The inherent difficulty of attempting to apply traditional principles of international law to such a legally confusing conflict is well illustrated by the issue of prisoners of war.

As combat units of the United States became heavily engaged in the war in 1965, the question arose as to the proper disposition for battlefield captives and others detained by U.S. units during military operations. In 1965 the United States determined to win over to the Vietnamese armed forces all individuals captured by U.S. forces. Such an arrangement is permissible under the Geneva Prisoner of War Conventions, which provide for the capturing power to release prisoners to a detaining power as long as both the capturing and the detaining powers fulfill certain obligations concerning the welfare of the prisoners.

While the legal basis for a transfer of prisoners was sound, carrying out the transfer was beset by serious legal and practical difficulties. The Republic of Vietnam regarded the Viet Cong as criminals who violated the security laws of South Vietnam and who consequently were subject to trial for their crimes. As indigenous offenders, the Viet Cong did not technically merit prisoner of war status, although they were entitled to humane treatment under Article 3, Geneva Prisoner of War Conventions. Under Article 12, the United States retained responsibility for treatment of its captives in accordance with the Geneva Conventions even after transfer of the captives to the South Vietnamese. At the same time, the United States was concerned that Americans held captive in North and South Vietnam receive humane treatment and be accorded the full benefits and protection of prisoners of war. In the south, where the government of South Vietnam had tried and publicly executed some Viet Cong agents, there had been retributory executions of Americans by the Viet Cong. In the north, the Hanoi government stated that it would treat captured American flyers humanely, but it would not accord them prisoner of war status as they were "pirates" engaged in unprovoked attacks on North Vietnam. Hanoi repeatedly threatened to try United States pilots in accordance with Vietnamese laws, but never carried out this threat. U.S. policy was for the United States to do all in its power to alleviate the plight of American prisoners. It was expected that efforts by the United States to ensure humane treatment for Viet Cong and North Vietnamese Army captives would bring reciprocal benefits for American captives.

Early in the war there had been some question in the United States command as to whether the struggle against the Viet Cong constituted an armed international conflict as contemplated in Article 2, Geneva Prisoner of War Conventions, or a conflict not of international nature, to which Article 3 would be applicable. With the infusion of large numbers of United States and North Vietnamese combat units and the coming of the Korean, Australian, Thai, and New Zealand contingents of the Free World Military Assistance Forces, any practical doubts as to the international nature of the conflict were resolved. Although North Vietnam made a strong argument that the conflict in Vietnam was essentially an internal domestic struggle, the official position of the United States, stated as early as 1965, and repeated consistently thereafter, was that the hostilities constituted an armed international conflict, that North Vietnam was a belligerent, that the Viet Cong were agents of the government of North Vietnam, and that the Geneva Conventions applied in full. This view was urged upon the government of South Vietnam, which acceded reluctantly, but subsequently came out in full support of the conventions.