Apart from Detachment 101 in Burma, OSS did not contribute much to the struggle against Japan until the last year of the war. Early in the conflict, Army and Navy commanders excluded OSS from their sectors of the Pacific, thereby forcing Donovan to fight the Japanese in the only region left open to him, the distant China-Burma-India Theater. The difficult geography involved and the complicated relations with America’s British and Chinese allies further delayed OSS’s deployments. When OSS finally began operating in strength, however, its operations made an impact on both the Japanese and on the shape of post-war policies in the region.

OSS had a difficult time winning authority or access to prosecute operations in China. The Nationalist regime in Chungking was a government in name only; Generalissimo Chiang Kai-shek was more China’s most powerful warlord than its national leader. He was fighting a war on two fronts—against the Japanese invaders on one side and against the Chinese Communists under Mao Zedong on the other. His secret police and intelligence chief, Tai Li, wanted American aid but had no intention of allowing Americans to operate independently on Chinese soil. American efforts to assist Chiang against the Japanese thus had to navigate a labyrinth of feuds and jealousies in Chungking before any implementation. Complicating matters still further, Tai Li demanded that American intelligence operations in China be run—wherever possible—by the office of Capt. Milton E. Miles, the commander of an unorthodox US Navy liaison unit.

Donovan in late 1943 personally told Tai Li that OSS would operate in China whether he liked it or not, but it still took a measure of subterfuge for Donovan’s officers to win a role there. The problem was bigger than Tai Li. At least a dozen American intelligence units operated in China over the course of the war, all of them competing for sources, access, and resources. Ironically, Donovan and OSS eventually “thrived on chaos,” according to historian Maochun Yu. OSS learned to provide services to American commanders that neither the Chinese nor other US organizations could match. Access and authorization followed in due course as OSS analysts and operatives proved that their methods materially assisted combat operations against the Japanese. For example, Gen. Claire L. Chennault, creator of the famous “Flying Tigers” and chief of US air power in China, needed accurate target intelligence. OSS filled his need through an “Air and Ground Forces Resources Technical Staff” (AGFRTS), and used this toe-hold to expand well beyond support for Chennault’s squadrons at Kunming. When a new theater commander, Lt. Gen. Albert C. Wedemeyer, began cleaning house and asserting his authority over all US intelligence operations in China, OSS allied itself with him and transferred AGFRTS from 14th Air Force to theater headquarters.

Although it never attained Donovan’s goal of full independence in China, OSS was a key player in operations and analysis there by the war’s end. On 9 August 1945—the day that Nagasaki was destroyed by an atomic bomb—Maj. Paul Cyr, leading a team of Chinese guerrillas on “Mission Hound,” dropped a strategic railroad bridge across the Yellow River near Kaifeng. Two spans of the bridge collapsed just as a Japanese troop train was crossing it. As soon as Japan capitulated, additional OSS teams ran “mercy missions” in Japanese-held territory to locate and evacuate Allied prisoners captured early in the war.

OSS plans and activities in China sparked inter-office arguments over US policy. China’s seemingly intractable troubles and the vast suffering of its people long confounded American policymakers. OSS officers who came aboard as China experts or sympathized with the Chinese people while serving there inevitably drew their own conclusions about the course of American diplomacy. Opinions in OSS ranged across the political spectrum, from admirers of Chiang in his struggles against Japanese invaders and Communist insurgents, to unabashed advocates of Communist leader Mao Zedong and his promise of justice for the peasantry through social revolution. Most OSS officers adhered to positions between these two poles, concerned about the dangers of Chinese Communism, but frustrated at the corruption of Chiang’s regime and its reluctance to make reforms to increase the effectiveness of American aid and to broaden its popular base.

Detachment 404 officers in Jessore, India, planning a supply drop, June 1945.

OSS officers in Thailand faced a different set of policy issues and demonstrated a high degree of teamwork in tackling them. Thailand had actually declared war on the United States and Great Britain after Pearl Harbor and was host to several Japanese bases. Washington had ignored Bangkok’s declaration, however, when it became clear that a portion of the Thai ruling elite quietly opposed Japan and hoped to keep their nation from being drawn more deeply into the conflict. For the rest of the war the British, Americans, and Japanese danced a complicated minuet around the possibility that the Thai opposition would rise against Japan and force Tokyo to divert badly needed combat troops to subjugating the country. Since the United States had no embassy in Bangkok, OSS officers eventually found themselves in the unlikely role of diplomats under the very noses of the Japanese troops guarding the city.

OSS efforts to contact the rumored Thai underground movement did not bear fruit until late 1944, after moderate opposition leaders in Bangkok ousted the dictatorship that had declared war on the Allies. Thai students recruited and trained by OSS (the “Free Thai”) and the British SOE were able to meet with underground leaders and even to broadcast reports from secret locations. Encouraged by the sudden surge of reporting, General Donovan in January 1945 dispatched two OSS majors, Richard Greenlee and John Wester, on a mission to Bangkok. Hiding in a spare palace by day and working by night, Greenlee and Wester confirmed that the Thai underground was secretly led by the de facto head of state, Prince Regent Pridi Phanomyong (codenamed Ruth). Pridi and his followers provided intelligence on the Japanese and offered to rise up in revolt, but they needed arms and training which only SOE and OSS could provide. To complicate matters, Pridi and the Free Thai (as well as OSS observers) suspected that the British harbored imperial designs on Thailand. If Americans could build a Thai guerrilla force, OSS men on the scene believed, the Thais could harass the Japanese and bolster a postwar claim to independence from British tutelage.

OSS officers promised American help for the projected Thai guerrillas. Back in Washington, the Department of State retroactively endorsed this commitment, which amounted to a change in US policy. In Bangkok, Greenlee, Wester, and their successors shuttled to meetings with Pridi and SOE in curtained limousines driven past the Japanese, who doubled their garrison in the country but dared not tear up the paper alliance between Thailand and Japan. The war ended in August 1945 before actual fighting broke out, but the diplomatic maneuvering continued. OSS officers close to the Thai peace delegation kept Washington informed of the course of Anglo-Thai peace talks and assisted American diplomats in advocating a settlement that ultimately helped ensure Thai independence.

A Royal Air Force Dakota supporting operations in
Thailand had to be unstuck the old-fashioned way at a
secret air strip in June 1945.

In China and Thailand, OSS graduated from a reporter of events to a shaper of American foreign policy. In China, OSS demonstrated that an American intelligence service aiding a foreign government against internal enemies could not remain aloof from the exhausting policy debates in Washington over the wisdom and means of backing the incumbent regime. By contrast, OSS officers in Thailand showed how much could be done through clandestine means to help a popular movement struggling against foreign domination.

Both lessons would echo in the Cold War, especially when the United States became embroiled in the Vietnam War. Even there, the OSS left a small but significant legacy for US foreign policy. Against the wishes of America’s French and Chinese allies, OSS “Mission DEER” had briefly aided Communist insurgent leader Ho Chi Minh in his fight against the Japanese in northern Indochina. Other OSS officers, such as Maj. Aaron Bank, arrived in Laos and in southern Vietnam as the war ended, and tried to make sense of the bewildering and violent nationalist and colonial rivalries among the French and Vietnamese factions there. OSS’s Col. Peter Dewey in Saigon tragically became the first American killed in Indochina when his jeep was ambushed by Communist guerrillas (apparently in a case of mistaken identity) in September 1945.