Continuing Tensions

The United States recognized Texas independence on March 3, 1837, the day before President Andrew Jackson left office. But Mexico refused recognition, considering Texas a rebel province. Texas attempted negotiations with Mexico, without success, and both sides came close to war several times in the following years. The two governments sent raids against each other, but Mexico never had the financial resources to mount a full-scale reconquest.

Meanwhile, the issue of Texas annexation became a dividing line in U.S. politics. The Van Buren administration (1837-1841) opposed Texas annexation. The Tyler administration (1841-1845) supported annexation, but Tyler's Whig Party opposed it. Texas annexation brought a “dark horse” candidate, James Knox Polk, the Democratic nomination for president in 1844. Polk won the election, and while he waited to take office, President Tyler opened negotiations for Texas to enter the United States. Polk completed the annexation on December 29, 1845.

Mexico considered this an act of war. Almonte, as ambassador to the United States, broke off diplomatic relations, and the two sides moved their armies to the region. General Zachary Taylor’s army crossed into a disputed zone, and war came when the two armies shed blood in that disputed zone in 1846. U.S. forces captured Mexico City in September 1847. In the Treaty of Guadalupe Hidalgo, signed on February 2, 1848, Mexico recognized the United States’s annexation of Texas, and sold the present-day southwestern United States.