In 1912, the regiment was called for service in the Mexican campaign. On the night of 5–6 May 1916, a detachment of nine troopers guarding Glenn Springs, Texas came under attack by a band of about 70 Villistas in the Glenn Springs raid, and three privates, William Cohen, Stephen J. Coloe, and Lawrence K. Rogers, were killed on American soil. The unit then joined General John J. Pershing's expeditionary forces in the Mexican Punitive Expedition against Pancho Villa and his forces during the summer of 1916, chasing bandits throughout the Mexican plains. The regiment then returned to Texas, where it began the task of patrolling the border until 1918, when it was called into service in Europe. The Treaty of Versailles was signed before the regiment could cross the Atlantic and the regiment resumed its border patrol mission.