blockade, use of naval forces to cut off maritime communication
and supply. Blockades may be used to prevent shipping from
reaching enemy ports, or they may serve purposes of coercion.
The term is rarely applied to land sieges. During the Napoleonic
wars, both France and Great Britain attempted to control neutral
commerce through blockades and embargoes which neither could
enforce with sufficient rigor. The Declaration of Paris (see
Paris, Declaration of) proclaimed (1856) that blockades were
henceforth to be announced to all affected parties and would be
legal only if effectively enforced against all neutrals. In both
World Wars blockades were made more effective by the employment,
in addition to naval vessels, of mines and aircraft. North
Vietnamese ports were mined and blockaded by the United States
during later stages of the Vietnam War. Blockades have also
occasionally been employed in times of peace as threats to
implement diplomacy, as in the blockade of Cuba by the United
States in 1962. The Columbia