United States signals intelligence programme under which RCA Global, ITT World Communications and Western Union Telegraph supplied copies of international telegram traffic to the Army Security Agency and then the National Security Agency, from August 1945 until it was terminated by the Secretary of Defense in May 1975. It ran for roughly thirty years with no warrant, no statute and no reliable evidence that successive presidents were briefed on it.
The Church Committee disclosed it in open session in late October 1975. It is regularly cited in UAP argument as the worked example that an intelligence programme can outlive everyone authorised to run it, most carefully in the afterword of The Day After Roswell, which states the limit of its own analogy: Shamrock shows a capability for long secrecy, not that any particular secret exists.
Connections
Church Committee · Central Intelligence Agency · The Day After Roswell · Philip J. Corso