Texas HistoryToday in Texas History: Congress Declares War on Mexico Over Texas Border Dispute

A skirmish in the Nueces Strip sparked a two-year war over land between the United States and Mexico — with the newly-annexed Texas found right in the middle.
May 13, 2020
In January of 1846, General Zachary Taylor — the same Zachary Taylor who would die just over a year into his presidency in 1850 — marched his U.S. army from Corpus Christi to the Rio Grande.

Since well before Texas won its independence from Mexico at the Battle of San Jacinto, or even the rebellion-igniting skirmish that was the Battle of Gonzales, the U.S. government — particularly President Andrew Jackson — had been eyeing the Lone Star State as its next territorial expansion. Its first president and governor, Sam Houston, supported this vision, too, as he was a disciple of Old Hickory.

The problem was, Mexico viewed the border separating it and Texas as the Nueces River. Texas, and the U.S. after its admission to the Union, considered that border to be the Rio Grande.

The conflict that would settle the question, the Mexican War, officially began on this day in 1846 as Congress declared war on its southern neighbor.

Two days earlier, President James K. Polk made the formal request for a congressional declaration of war. The charge derived from a skirmish involving Taylor and an ambush from Mexican forces on April 25.

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Polk had been trying to negotiate the acquisition of the land since becoming president.

Former Mexican President Antonio López de Santa Anna, after being captured at San Jacinto, had agreed to terms that set the boundary at the Rio Grande. After the Nueces strip skirmish, Mexicans ousted their then-President Mariano Paredes and reinstated Santa Anna to the position from which he had been exiled two years earlier.

Texas was admitted to the Union in 1845, but the dispute over its southern boundary had not been resolved.

The Mexican government had been resistant to Polk’s appeals, and so he looked for other opportunities, settling on outright commandeering the land with a show of force. When the Mexicans took the bait, Polk had his “spilling of American blood on American soil.”

Polk would assert the territory belonged to Texas under the terms agreed upon by Santa Anna himself 10 years earlier. But the Mexicans saw that as a coerced agreement, null and void, and Polk even received opposition from Americans— not the least of which was another future president, Abraham Lincoln. The then-congressman from Illinois issued his famous “spot resolution” in 1847 protesting the conflict.

Lincoln asked Polk to specify “whether the particular spot of soil on which the blood of our citizens was so shed, was, or was not, our own soil.”

Just as it was 10 years earlier, Texas was again the epicenter of an armed conflict against Santa Anna. The first major battle was at Palo Alto and largely ended in a stalemate. Led by General Mariano Arista, the Mexican army retreated to Resaca de la Palma — from which they were driven the next day.

The American forces then moved south into Mexico and occupied Monterrey — buttressed by John Coffee Hays’ Texas Mounted Rifles, or Texas Rangers, as they would come to be known. All the while, other sections of the American forces moved west to capture New Mexico and, eventually, California.

In Mexico, Santa Anna and his army attempted a maneuver to defeat Taylor’s army and then the newly formed force under the command of General Winfield Scott. The move did not go as planned as Taylor’s 4,600-man force narrowly defeated Santa Anna’s nearly 15,000-man force at Buena Vista.

Soon after, Scott’s newly commissioned force of 10,000 set foot on Mexican soil near Veracruz.

This militaristic overachieving at Buena Vista by the American army became a theme as similar triumphs occurred at Cerro Gordo, Contreras, Churubusco.

Eventually, the Americans surrounded Mexico City and besieged the capital until it officially surrendered in February of 1848. The Treaty of Guadalupe Hidalgo was drafted and signed by both sides, securing Arizona, California, and New Mexico in addition to setting Texas’ southern boundary at the Rio Grande River.

Sections of Colorado, Nevada, and Utah were also obtained.

After this loss, Santa Anna was again exiled, this time to Jamaica.

President Polk, while losing out on the “quick war” he had envisioned, still managed to secure the land holdings, and much more, he had sought after.

America now had control over the rest of what would become the continental United States.

Many giants of American history gained the battle experience that would help them in the looming conflict 15 years down the road, including Ulysses S. Grant, Robert E. Lee, George McClellan, Stonewall Jackson, George Meade, and George Pickett.

Additionally, during the two-year war, the Texas Rangers gained much of the notoriety they boast today. Taylor called them his “eyes and ears” and Mexican guerillas termed them “los diablos Tejanos.” 

But with the American army taking over enforcement duties, the Rangers, for a decade, became “little more than an historical expression.”

In the span of a decade, Texas had been the focus of two international conflicts and moved from the top of the U.S.’s wish list to the top of its list of assets.


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Brad Johnson

Brad Johnson is an Ohio native who graduated from the University of Cincinnati in 2017. He is an avid sports fan who most enjoys watching his favorite teams continue their title drought throughout his cognizant lifetime. In his free time, you may find Brad quoting Monty Python productions and trying to calculate the airspeed velocity of an unladen swallow.