On This Day in History: U.S. Declares War on Mexico

From History.com

On May 13, 1846, the U.S. Congress overwhelmingly votes in favor of President James K. Polk’s request to declare war on Mexico in a dispute over Texas.

Under the threat of war, the United States had refrained from annexing Texas after it won independence from Mexico in 1836.But shortly before leaving office and with the support of President-elect Polk, Tyler managed to get a joint resolution passed by Congress on March 1, 1845.

In November 1845, Polk sent the diplomat John Slidell to Mexico to seek boundary adjustments. After the mission failed, the U.S. army under Gen. Zachary Taylor advanced to the mouth of the Rio Grande, the river that the state of Texas claimed as its southern boundary.

Texas was admitted to the union on December 29, 1845.

Mexico, claiming that the boundary was the Nueces River to the northeast of the Rio Grande, considered the advance of Taylor’s army an act of aggression and in April 1846 sent troops across the Rio Grande. Polk, in turn, declared the Mexican advance to be an invasion of U.S. soil, and on May 11, 1846, asked Congress to declare war on Mexico, which it did two days later.

Many of the military leaders on both sides of the American Civil War fought as junior officers in Mexico.

For the Union: Ulysses S. Grant, George B. McClellan, William T. Sherman, George Meade, William Rosecrans, and Ambrose Burnside.

For the Confederate States of America were Robert E. Lee, Stonewall Jackson, James Longstreet, Joseph E. Johnston, Braxton Bragg, Sterling Price, and Jefferson Davis.

After nearly two years of fighting, peace was established by the Treaty of Guadalupe Hidalgo, signed on February 2, 1848.

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