This map shows the land area called the Republic of Texas. Notice that both Texas and the United States claimed some of the same land. In 1845 the independent nation of Texas became a state of the United States of America. “Remember the Alamo” became the cry for the remainder of the Texans’ army. This army, led by Sam Houston, finally defeated the Mexican army on April 21, 1836. Texas was now a free, independent nation. Mexico had lost the first of its northern lands. During this time an idea became very powerful in the United States. The idea was known as Manifest Destiny. This idea stated that the United States of America was destined to become a nation from the Atlantic to Pacific oceans. This idea was being pushed in the United States Senate by the senator from Missouri, Thomas Hart Benton. California and all the land west of the Mississippi River was the American dream. But all this land was within the country of Mexico. Now, Texas was free and the Manifest Destiny dream of the United States of a nation from “sea to shining sea” became even stronger. In 1845, the American government offered to buy Mexican land in the Southwest and California. Mexico would not sell its land. On April 25, 1846, the United States declared war on Mexico. 66  Chapter 6 • Territory of New Mexico