(especially in the case of War Plan Crimson, the invasion of Canada). Some of the war plan colors were revised over time, possibly resulting in confusion. Although the US 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. The Americas War Plan Green 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. Thus War Plan Green was developed. In 1916, U.S. troops under General John Pershing invaded Mexico in search of Pancho Villa, whose army had attacked Columbus, New Mexico; earlier, American naval forces had bombarded and seized the Mexican port of Veracruz, and forced Victoriano Huerta to resign the presidency. 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 US and Mexico. Relations with Mexico remained tense into the 1920s and 1930s. Beyond Mexico Additionally, between the American Civil War and World War I, the American military intervened in the affairs of Latin American countries, including Colombia, Panama, Haiti, Cuba, and Nicaragua. In doing so, parts of "Gray" and "Purple", plans were considered although never officially activated. Multilateral war plans Some plans were expanded to include war against a coalition of hostile powers. The most detailed was War Plan Red-Orange, which detailed a two-front war against Britain and Japan. This was the contingency which most worried U.S. war planners, since it entailed a two-ocean war against major naval powers. Although the 1902 Anglo-Japanese Alliance was terminated by the 1921 Four-Power Treaty, American generals did not rule out the possibility of Britain wanting to seek an alliance with Japan again if war ever broke out. Theories developed in War Plan Red-Orange were useful during World War II, when the United States engaged