[53]

Mexican–American War
Main article: Mexican–American War
Battle of Monterrey Published 1847
After rising tensions with Mexico following the United States annexation of Texas, war broke out in 1846. During the conflict, Grant distinguished himself as a daring and competent soldier.[54] Before the war President John Tyler had ordered Grant's unit to Louisiana as part of the Army of Occupation under Major General Zachary Taylor.[55] In September 1846, Tyler's successor, James K. Polk, unable to provoke Mexico into war at Corpus Christi, Texas, ordered Taylor to march 150 miles south to the Rio Grande. Marching south to Fort Texas, to prevent a Mexican siege, Grant experienced combat for the first time on May 8, 1846, at the Battle of Palo Alto.[56]
Grant served as regimental quartermaster, but yearned for a combat role; when finally allowed, he led a charge at the Battle of Resaca de la Palma.[57] He demonstrated his equestrian ability at the Battle of Monterrey by volunteering to carry a dispatch past snipers, where he hung off the side of his horse, keeping the animal between him and the enemy. Before leaving the city he assured some wounded Americans he would send for help.