Tyler Signs Texas Annexation: War Looms with Mexico

President John Tyler signed the joint resolution authorizing the annexation of the Republic of Texas on March 1, 1845, three days before leaving office. The resolution offered Texas admission to the Union as a state rather than as a territory, bypassing the normal annexation process and avoiding the two-thirds Senate majority that a formal treaty would have required. Texas had been an independent republic since 1836, when American settlers and Tejanos rebelled against Mexican rule, defeated General Santa Anna at the Battle of San Jacinto, and established a government under Sam Houston. The republic had sought annexation to the United States almost immediately, but the issue was politically toxic because Texas would enter as a slave state, upsetting the balance between free and slave states in the Senate. Tyler, a Virginia slaveholder who had become president after William Henry Harrison's death in 1841 and who had been expelled from his own Whig Party, saw annexation as his legacy. He negotiated an annexation treaty that the Senate rejected in June 1844. He then pushed for a joint resolution of both houses of Congress, which required only a simple majority. It passed the House 120 to 98 and the Senate 27 to 25. Mexico had never recognized Texas independence and considered annexation an act of war. The Mexican government broke diplomatic relations with the United States immediately. President James K. Polk, who succeeded Tyler, sent troops to the disputed territory between the Nueces River and the Rio Grande. A clash between American and Mexican forces in April 1846 provided the justification for the Mexican-American War. The war ended in 1848 with the Treaty of Guadalupe Hidalgo, which transferred California, New Mexico, Arizona, Nevada, Utah, and parts of Colorado and Wyoming to the United States. Texas annexation thus triggered a conflict that increased the size of the United States by roughly one-third. It also intensified the sectional crisis over slavery that would lead to the Civil War fifteen years later.