The Battle of Resaca de la Palma:
On May 8, 1846, the Mexican-American War
saw its first major battle as two armies squared off at the Battle of Palo Alto
. The battle was inconclusive and the two met again the next day a few miles away at the battle of Resaca de la Palma, known in Mexico as Resaca de Guerrero. Although the Mexicans held a good defensive position, they were scattered by the Americans, who used their artillery and cavalry to good effect. Taken together, the battles were a win for the Americans, who proceeded to invade Mexico, making their way towards Monterrey and Saltillo.
The American Invasion:
Tensions had been high between Mexico and the USA since the 1830's, when Texas split from Mexico. By 1846, the USA had its eye on Mexico's western possessions such as California and New Mexico, and Mexico was still furious over Texas joining the USA
. War was practically inevitable. In early 1846, a series of border skirmishes escalated into all-out war. The USA took the offensive, sending a large army under General Zachary Taylor
into the contested part of the border between Mexico and Texas. Meanwhile, Mexican General Mariano Arista
was in the north with a large army set to resist the invasion.
The Battle of Palo Alto:
On May 8, the two armies met at the Battle of Palo Alto. Although the Mexicans enjoyed a good defensive position and numerical superiority, the USA won the battle, largely because of a new battlefield unit never seen before: the flying artillery. Flying artillery were small squads of cannons and mortars designed to move swiftly around a battlefield to where they were most needed. At the Battle of Palo Alto, the American flying artillery had carried the day. The cannons and mortars had killed the Mexicans in their defensive formations, forcing them to attack, and then the same cannons had repulsed the cavalry and infantry charges sent to destroy them.
The Mexicans disengaged from the Battle of Palo Alto in an orderly fashion, moving a few miles away to Resaca de la Palma, a dry, shallow creek bed surrounded by rough vegetation. They had learned to respect the American artillery, and so instead of fighting on open ground as they had the previous day, they dug in and prepared for a defensive fight. They also received reinforcements during the night, bringing their total strength to some 4,000 soldiers. General Taylor rested his men that night and marched in pursuit the following morning, eager to press his advantage: he had about 1,700 men.
The Battle of Resaca de la Palma:
The Americans attacked fiercely, sending a force of dragoons after the Mexican artillery and firing their cannons wherever they thought the Mexicans were hiding in the dense underbrush. Although the dragoons failed to capture the artillery, a detachment of infantry did. The Americans soon controlled the center of the battlefield, which included the road to Matamoros. The Mexicans, still edgy after the one-sided combat of the day before, saw their center collapse and soon broke. General Arista tried to rally the troops, to no avail: Arista himself left so hurriedly that he left behind his tent, complete with silver, his writing table and some of his papers.
Aftermath of the Battle of Resaca de la Palma:
Although they had chosen a good defensive position which mostly neutralized the Americans' advantage in artillery, the Mexicans were routed. Arista and his men retreated deep into Mexican territory, essentially ceding all of the territory between the border and the fortified city of Monterrey to the invaders. Reports of Mexican casualties range between 300 and 1,200, with many desertions. The Americans lost 34 killed and 113 wounded in two days of battle, according to Taylor's report. About one hundred Mexicans were taken prisoner, including a general and some other officers.
General Arista had developed a sound battle plan: the dense chaparral had, in fact, hidden his men from the dreaded American artillery and he managed to do more damage than he had at Palo Alto. He lost the battle when he lost his artillery and key elements of his center broke. The Mexicans fled all the way to the Rio Grande: the Americans pursued them but no major battle ever ensued. Once the Mexicans were across, they were forced to march all the way to Monterrey. There, the skilled Arista was relieved of command and replaced with General Pedro de Ampudia.
Taken together, Palo Alto and Resaca de la Palma were disastrous for Mexico. Speaking in terms of the overall war effort, their best chance had been to stop the invaders cold at the border: instead they lost thousands of their best troops through battle and desertion. Had Arista at least fought to a draw, the effect on Mexican national morale may have been tremendous. The two battles showed Mexican weaknesses that would be repeated throughout the war: they had poor officers and inferior artillery.
For the Americans, the battles were significant early wins: they proved to them that they could win while in enemy territory. They showed the value of the flying artillery, which they would use to great effect in the coming months. They also greatly increased morale among the troops and allowed politicians back in the USA to spin the war as a winning effort.
Eisenhower, John S.D. So Far from God: the U.S. War with Mexico, 1846-1848. Norman: the University of Oklahoma Press, 1989
Henderson, Timothy J. A Glorious Defeat: Mexico and its War with the United States.New York: Hill and Wang, 2007.
Hogan, Michael. The Irish Soldiers of Mexico. Createspace, 2011.