Chapter One"American NationalismAchieves an Ominous Fulfillment"On Saturday evening, February 19, 1848, a little after dusk, a special courier arrived in Washington at the end of a remarkably rapid journey from Mexico City. He had left the Mexican capital scarcely two weeks earlier, had hastened through the mountains and down to Vera Cruz, where he took ship to Mobile, and from there had pushed on in only four days to Washington. His first act upon arriving was to deliver to Mrs. Nicholas P. Trist two letters from her husband in Mexico, after which he went on to the house of Secretary Of State James Buchanan. To Buchanan, he delivered a treaty which Trist had negotiated at Guadalupe Hidalgo on February 2 to terminate the war with Mexico. By this treaty the United States was to acquire an area of more than 500,000 square miles, including what is now California, Nevada, and Utah, most of New Mexico and Arizona, and part of Wyoming and Colorado--next to the Louisiana Purchase, the largest single addition to the national domain.More than a century later, readers in Los Angeles, San Francisco, Salt Lake City, Phoenix, Tucson, Albuquerque, Santa Fe, and even Las Vegas might suppose that such a vast acquisition would have been hailed with wild enthusiasm, but this was by no means true. On the contrary, James K. Polk, a purposeful man then in the third year of his presidency, found the treaty most unwelcome. True, its terms were closely in accord with what he had wanted when he sent Trist to Mexico in the preceding April. But since that time, a great deal had happened. In September, General in Chief Winfield Scott had marched victorious into Mexico City. The occupation of thecapital had brought Mexico to a crisis during which Santa Anna resigned as president, leaving the government one step away from collapse and the country itself ripe for acquisition. These events had stimulated some of the eagle-s