diplomatic communications. By doing so, the United States could
discern Soviet intentions toward the U.S. and the West. However,
VENONAintercepts also played a central role in identifying Julius
and Ethel Rosenberg, Klaus Fuchs, and Alger Hiss, who, along with
others, constituted a Soviet “atom spy” ring that penetrated the Man-
hattan Project and passed secret information about the atomic bomb
to the Soviets.
Julius and Ethel Rosenberg, husband and wife, were convicted of
spying for the Soviet Union in 1951 and were executed in 1953. Both
steadfastly proclaimed their innocence. Their case sparked domestic
and international protests that they had been falsely convicted as part
of an upswing in anti-Semitic and anticommunist hysteria that
gripped the United States during the McCarthy Era in the early
1950s. The case remains controversial, although VENONAevidence
suggests their guilt. VENONAcame to an end in 1980, and the U.S.
government made VENONA intercepts public in 1995. See also
SIGNALS INTELLIGENCE.VIETNAM WAR. The Vietnam War was a Cold Warconfrontation
between the U.S.-backed South Vietnamese regime and communist
North Vietnam and its guerrilla allies, the Viet Cong, that began in
1956 and lasted until 30 April 1975. Vietnam had been divided in
1954 by an agreement that pledged a plebiscite on unification by- South Vietnam, with the support of its ally, the United States,
backed out of the deal, sparking an insurgency by the Viet Cong, pre-
viously the Viet Minh, who had battled French occupation forces and
defeated them in 1954.
Direct U.S. military involvement in the war began in the early
1960s. Throughout 1961, President John F. Kennedycame under in-
tense pressure from his military chiefs and political advisors to send
American troops to Laos and South Vietnam to stem the flood of
communist military successes and prop up the faltering South Viet-
namese regime. President Kennedy committed U.S. advisors, train-
ing, and equipment to the South Vietnamese armed forces later that
year, hoping to stiffen South Vietnamese resolve. By the time of Pres-
ident Kennedy’s assassination on 22 November 1963, however, it had
become clear that the situation was rapidly deteriorating in favor of
communist forces. The U.S.-sanctioned overthrow of South Viet-
namese president Ngo Dinh Diem and the installation of successor
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