Mexican Border War

The Mexican Border War, also known as the Border Campaign, refers to a series of military engagements which took place between the United States military and several Mexican factions in the Mexican–American border region of North America during the Mexican Revolution.

From the beginning of the Mexican Revolution in 1910, the United States Army was stationed in force along the border and, on several occasions, fought with Mexican rebels or regular federal troops. The height of the conflict came in 1916 when revolutionary Pancho Villa attacked the American border town of Columbus, New Mexico. In response, the United States Army, under the direction of General John J. Pershing, launched a punitive expedition into northern Mexico, to find and capture Villa. Although Villa was not captured, the US Army found and engaged the Villista rebels, killing Villa's two top lieutenants. The revolutionary himself escaped, and the American army returned to the United States in January 1917.

Conflict at the border continued, however, and the United States launched several smaller operations into Mexican territory until after the American victory in the Battle of Ambos Nogales in August 1918, which led to the establishment of a permanent border wall. Conflict was not limited to battles between Villistas and Americans; Maderistas, Carrancistas, Constitutionalistas and Germans also engaged with American forces in that period. The Bandit War in Texas was part of the Border War.

The German Empire, a major trading partner with Mexico and a rival of the United States and its allies, was involved. In 1914, the United States occupied Veracruz, aiming to cut off supplies of ammunition from the German Empire to Mexico at the start of World War I. In 1917, the British government intercepted a German telegram which offered the Mexican President financial support in recapturing the territories acquired by the United States through the Texas annexation and the Mexican Cession. In exchange, the German Empire wanted Mexico's formal support in anticipation of a hypothetical United States entry into the war in Europe. While the offer was not accepted, a small German military presence could be observed in later battles along the border, such as the Battle of Ambos Nogales.