1. U.S. RAINBOW War Plans
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.
Notes from

2. War Plans Violet (Latin America) White (Domestic U.S.) Orange (Japan)
Red/Crimson (Britain/Canada)
Gray (Azores Islands)
Brown (Philippines)
Tan (Cuba)
Yellow (China)
Indigo (Iceland)
Purple (A South American republic)
Violet (Latin America)
White (Domestic U.S.)
Orange (Japan)
Black (Germany)
Gold (France)
Green (Mexico)

3. Plans Red/Crimson RED CRIMSON Potential war with Britain (Plan Red).
Created because American planners thought that Britain’s imperial reach would bring it into conflict with the U.S.
CRIMSON
Potential war with Canada (Plan Crimson).
Focused on invading Montreal and Quebec & stopping British reinforcements from reaching Canadian forces.

4. Plan Black Potential war with Germany
Implemented in case France fell and the Germans attempted to seize French possessions in the Caribbean, or launch an attack on the U.S. eastern seaboard.

5. Plan Orange Potential war with Japan
Formed the basis of the actual campaign against the Japanese during World War II.
Plan Orange wanted to establish lines of communication from U.S. through the Carolina & Marianas Islands to Australia.

6. What happens if there is war on multiple fronts?
American war planners realized that the United States faced the possibility of war on multiple fronts against a coalition of enemies.
To that end, the Joint Planning Board developed a new series of war plans, the "Rainbow" plans.

7. RAINBOW PLANS
Defensive war to protect the United States and the Western Hemisphere 10 degrees south latitude. The United States was assumed to be without major allies.
Assumed that that United States would be allied with France and Britain.
Same as Plan Orange, where Western Hemisphere defense would be secured, as provided in RAINBOW 1.
Same as RAINBOW 1, but extended the American mission to include defense of the entire Western hemisphere.
Assumed that the United States was allied with Britain and France and provided for offensive operations by American forces in Europe, Africa, or both.