The USS Pueblo: “The cost of this deployment to the nation in terms of the amount of cryptologic material compromised was enormous.”
Last week’s episode of AMC’s Mad Menfeatured a passing reference to the USS Pueblo, an American SIGINT ship captured by North Korean forces on January 23, 1968, and the only commissioned US Navy ship still in foreign possession. While the reference was short, the dramatic, real-life account of the Pueblo was an intelligence breach of enormous proportions, and, followed by the downing of a US reconnaissance EC-121 plane over the Sea of Japan in 1969 by a North Korean MiG-17,encouraged the Nixon Administrationto develop contingency plans that would allow the use of tactical nuclear weapons against Pyongyang.
On January 8, 1968, the Pueblo sailed from Sasebo, Japan, to its position off the North Korean coast with the mission to “draw emissions from North Korean communications.” At 12 PM on January 23, a day after North Korea attempted to assassinate South Korean President Pak Chong-hui, the Pueblo was approached by a North Korean vessel challenging its nationality. At 1:28 the Pueblo reported that the Koreans intended to fire on them, at 2:10 the crew requested “some help,” and at 2:25 reported they had “been directed to come to a stop. Destruction incompleted. Some publications will be compromised.” An epic understatement according to the 1992 National Security Agency report of the incident declassified in 2012, which claims that there was a massive amount of classified material and cipher equipment confiscated by the North Koreans and likely passed on to the Soviet Union and China.
The full extent of the classified information and equipment on board may have been unknown to President Johnson and his advisors at the time, who, during a lunch meeting on January 29, were more concerned with how the Pueblo’s capture would affect their position in Vietnam. Johnson was especially sensitive to concerns that any action against North Korea would detract from troop levels in Vietnam, arguing, “[t]here is no need to call up the reserves for Vietnam. In fact, General Westmoreland would rather go without the reserves in Vietnam. ..Of course we could call up the reserves at anytime without Korea if we wanted.”
On January 30, the same day the Tet Offensive began, the President was pushed by House Minority Leader Gerald Ford, the man LBJ accused of spending “too much time playing football without a helmet,” to be more critical of the events that lead to the Pueblo’s capture. Ford claimed he would have gotten rid of all the intelligence equipment on board, even if it meant sinking the vessel himself. Johnson, for his part, admitted he would have requested help earlier. Though, the president conceded that “[p]robably the luckiest thing that happened to us was that we did not send people in there and have another Bay of Pigs. Darkness was approaching. Snow was falling.”
The blistering NSA account of the intelligence lost with the Pueblo contradicts the president’s claim.
On December 23, 1968, the US wrote (and quickly rescinded) an apology for spying, and without any military action being taken, the crew of the USS Pueblo was released. The Pueblo Crisis spurred the Nixon administration to develop contingency plans for Pyongyang’s aggression that included “a long list of nearly 25 military options, ranging from evacuation of U.S. personnel in a crisis to limited nuclear strikes using kiloton-range nuclear weapons that involved possible casualties in the thousands.”
For a more in-depth account of the Pueblo incident or US-North Korean relations, see the Archive’s briefing books, The Secret Sentry Declassified and How Do You Solve A Problem Like Korea?
 The amount of intelligence compromised as a result of the Pueblo incident was magnified by the discovery of the Walker Sky network, which operated within the US Navy and passed high-level ciphers to the Soviets from 1967 through the mid-1980s, meaning that the Soviets were receiving US ciphers by the time they possibly had access to the USS Pueblo decoding equipment. See page 157 of the NSA report for more.