Wilmot Proviso
In 1846 Bowles was one of several men who helped organize a local militia company to fight in the Mexican–American War, the result of federal legislation such as the Wilmot Proviso. His company was assigned to the 2nd Indiana Volunteer Regiment. Bowles was elected as a colonel in the regiment on August 28, 1846, and received a commission in the U.S. Army at Brazo Santiago, Texas, on July 31.