What did the declassified documents reveal?

The record before us is a declassified Central Intelligence Agency assessment of Chinese Communist communications and the People’s Republic of China’s intervention in the Korean War, compiled in June nineteen ninety‑six and released to the public in August two thousand eight. This material was made available through a Freedom of Information Act request filed with the Central Intelligence Agency. The declassification was authorized jointly by the National Security Agency and the Central Intelligence Agency on August nineteenth, two thousand eight, under Executive Order one two nine fifty‑eight, as amended. The full text is hosted at the Black Vault archive. The document opens with an expanded version of an address delivered by Guy R. Vanderpool at the Cryptologic History Symposium in October nineteen ninety‑three, titled “A Risk We Knowingly Took.” It recounts that on twenty‑five October, nineteen sixty, four Chinese Communist armies launched a sudden attack on General Douglas MacArthur’s United Nations forces in the approaches to the North Korean border with the People’s Republic of China. The United Nations units withdrew to defensive positions. When General MacArthur resumed the advance a month later, the Joint Chiefs of Staff warned that the offensive might develop into a major clash with the Chinese and could draw the Soviet Union into a general war. The Joint Chiefs asked General MacArthur whether he could keep United States units away from the Chinese border to reduce that danger. General MacArthur rejected the proposal, calling any such change a betrayal of the Korean people, an appeasement of Communist aggression, and a tribute to international lawlessness. He told the Joint Chiefs that “the entry of Chinese Communists was a risk we knowingly took at the time we committed our forces.” Within two days, nine People’s Republic of China armies overwhelmed the United Nations forces. Survivors of the first assaults reported long columns of Chinese troops moving past to cut off retreat. General MacArthur later cabled the Joint Chiefs that he was now facing “an entirely new war.” The record emphasizes that Chinese Communist communications were not new to American cryptologists. It notes that the United States first obtained communications intelligence on the Chinese Communists from Japanese traffic during the Second World War. Intercepts reported Communist activity well before the Korean conflict. The document also records Soviet diplomatic statements from the mid‑forties, including remarks by Soviet Foreign Minister Molotov that Russia did not propose to interfere in Chinese affairs and did not support the Chinese Communists, and a comment by Marshal Joseph Stalin to Ambassador William Averell Harriman describing members of the Chinese Party as “margarine Communists.” It further recounts that General George C. Marshall, while serving as President Truman’s special envoy to China in nineteen forty‑six, sought cryptologic support from the Army…

Why was this case declassified?

This material entered the public record through the U.S. declassification and Freedom of Information Act (FOIA) process. The originating source document is linked on this page so the citation chain is auditable.

Central Intelligence Agency Assessment

◆ BLUF — The short version

The record before us is a declassified Central Intelligence Agency assessment of Chinese Communist communications and the People’s Republic of China’s intervention in the Korean War, compiled in June nineteen ninety‑six and released to the public in August two thousand eight.

Date: AUG 1 · 2026
Release: Declassified · U.S. public record (FOIA)
Source document: View the primary source document

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What was Central Intelligence Agency Assessment about?: The record before us is a declassified Central Intelligence Agency assessment of Chinese Communist communications and the People’s Republic of China’s intervention in the Korean War, compiled in June nineteen ninety‑six and released to the public in August two thousand eight.
Why was this case declassified?: This material entered the public record through the U.S. declassification and Freedom of Information Act (FOIA) process. Storyflo narrates it directly from the public release.

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