Congress was also informed that the American army under Gen. Zachary Taylor had been ordered to occupy, and had occupied, the western bank of Nueces river, beyond which Texas had never hitherto exercised jurisdiction. On December 29 Texas was admitted into the Union, and two days later an act was passed extending the United States revenue system over the doubtful territory beyond the Nueces. Even these measures did not elicit a declaration of war from the Mexican authorities, who still declared their willingness to negotiate concerning the disputed territory between the Nueces and the Rio Grande. These negotiations, however, came to nothing, and the president, in accordance with Gen. Taylor's suggestion, ordered a forward movement, in obedience to which that officer advanced from his camp at Corpus Christi toward the Rio Grande, and occupied the district in debate. Thus brought face to face with Mexican troops, he was attacked early in May with 6,000 men by Gen. Arista, who was badly beaten at Palo Alto, with less than half that number. The next day Taylor attacked Arista at Resaca de la Palma, and drove him across the Rio Grande.
On receipt of the news of these events in Washington, President Polk sent a message to congress, in which he declared that Mexican troops had at last shed the blood of American citizens on American soil, and asked for a formal declaration of war.
