During the 1920s and 1930s, the United States military
developed a number of Color-coded War Plans
to outline potential U.S. strategies for a variety of hypothetical war scenarios. The plans, which were developed by the Joint Planning Committee (which later became the Joint Chiefs of Staff
) were officially withdrawn in 1939, in favor of five Rainbow Plans developed to meet the threat of a two ocean war against multiple enemies.
The best-known of these plans (although they were secret at the time) is probably War Plan Orange, a series of contingency plans for fighting a war with Japan alone, unofficially outlined first in 1919, then officially in 1924. Orange formed some of the basis for the actual campaign against Japan in World War II and included the huge economic blockade from mainland China.
War Plan Red
, a more hypothetical plan for war against Britain
, caused a stir in American-Canadian relations when declassified in 1974. A related plan was War Plan Crimson, which envisioned a limited war with the British Empire concentrating on an invasion of Canada. In this color scheme, the UK was "Red," Canada "Crimson," India "Ruby," Australia "Scarlet" and New Zealand "Garnet."
Though the possibility of a war between the United States and Great Britain diminished greatly after World War I
, the plan was kept updated as late as the 1930s. (There was concern in Washington that if Britain fell to the Axis
during World War II, American forces would have to occupy Canada.)
List of Color-coded War Plans
- War Plan Red was a plan for war against Britain and Canada. British territories had war plans of different shades of red -- the UK was "Red," Canada "Crimson," India "Ruby," Australia "Scarlet" and New Zealand "Garnet."
- War Plan Black was a plan for war with Germany. The best-known version of Black was conceived as a contingency plan during World War I in case France fell and the Germans attempted to seize French possessions in the Caribbean, or launch an attack on the eastern seaboard.
- War Plan Brown dealt with an uprising in the Philippines.
- War Plan Citron was for Brazil.
- War Plan Emerald was for intervention in Ireland in conjunction with War Plan Red.
- War Plan Gray dealt with invading a Caribbean republic.
- War Plan Green involved war with Mexico or what was known as "Mexican Domestic Intervention" in order to defeat rebel forces and establish a pro-American government. War Plan Green was officially canceled in 1946.
- War Plan Gold was a plan for war with France and French Caribbean possessions.
- War Plan Indigo involved an invasion of Iceland. In 1941, during the German occupation of Denmark, the British invaded Iceland and the U.S. actually did occupy the island nation, relieving British units during the Battle of the Atlantic.
- War Plan Lemon was for Portugal.
- War Plan Olive was for Spain.
- War Plan Orange was a plan for war against Japan, which formed some of the basis for the actual campaign against Japan in World War II.
- War Plan Purple dealt with invading a Central American republic, or possibly with Russia (There may have been two different Purples).
- War Plan Silver was for war with Italy.
- War Plan Tan was for intervention in Cuba.
- War Plan White dealt with a domestic uprising in the U.S., and later evolved to Operation Garden Plot, the general U.S. military plan for civil disturbances and peaceful protests. Parts of War Plan White were used to deal with the Bonus Expeditionary Force in 1932. Communist insurgents were considered the most likely threat by the authors of War Plan White.
- War Plan Yellow dealt with war in China - specifically, the defense of Beijing and relief of Shanghai during the Second Sino-Japanese War. War Plan Violet was for intervention in Chinese domestic events.
In addition there were combinations such as Red-Orange, which was necessitated by the Anglo-Japanese military alliance which expired in 1924.
In all of these plans, the U.S. referred to itself as "blue."
Many of the war plans are extremely hypothetical, considering the state of international relations in the 1920s and it was entirely within keeping with the military planning of other nation states. Often, junior military officers were given the task of updating each plans to keep them trained and busy (this was especially true in the case of War Plan Crimson, the invasion of Canada). Some colors of the war plans changed over time with new revisions which can result in confusion.
Interestingly, although the U.S. had fought its most recent war against Germany and would fight another within twenty years, intense domestic pressure emerged for the Army to halt when it became known that the Army was constructing a plan for a war with Germany; isolationists opposed any consideration of involvement in a future European conflict. This may have encouraged the Army to focus on more speculative scenarios for planning exercises.
On the other hand, some of these plans were designed to cope with real threats and eventualities. For instance, Japan had used the opportunity afforded by World War I to establish itself as a major power and a strategic rival in the Pacific Ocean. Following World War I, most American officials and planners considered a war with Japan to be highly likely. It was reverted when the civilian government temporarily halted the program of military expansion, which was not to resume until 1931. Notably, Orange is the longest and most-detailed of the plans, and many of its elements were carried over into Plan Rainbow Five, the current plan at the time of Pearl Harbor.
Some plans were expanded to include war against a coalition of hostile powers. The most detailed was Red-Orange, based on a two-front war against a British-Japanese alliance. This was the contigency which most worried U.S. war planners, since it entailed a two-ocean war against major naval powers. Theories developed in wargaming Red-Orange were useful during World War Two, when the United States engaged the Axis in both the Atlantic and Pacific simultaneously.
War Plan Green was also likely to be used. During the 1910s relations between Mexico and the United States were often volatile. In 1912, U.S. President William Howard Taft
considered sending an expeditionary force to protect foreign-owned property from damage during the Mexican Revolution. In 1916, U.S. troops under General John Pershing
invaded Mexico in search of Pancho Villa
, whose rebel band had attacked Columbus
, New Mexico
; earlier, American naval forces had bombarded and seized the Mexican
port of Veracruz
, and forced dictator Victoriano Huerta
to resign. In 1917, British intelligence intercepted a telegram from the German foreign ministry to its embassy in Mexico City offering an alliance against the United States and assistance in the Mexican reconquest of the Southwest. Released to American newspapers, the Zimmermann Telegram
helped turn American opinion against Germany and further poisoned the atmosphere between the USA and Mexico. Relations with Mexico remained tense into the 1920s and 1930s.
Additionally, between the United States Civil War and World War I, the American military frequently intervened in the affairs of Latin American countries, including Panama, Haiti, Cuba, and Nicaragua. This policy continued during the 1920s and 1930s, and parts of "Gray" and "Purple," although never officially activated, were used.