Mexican war. Starting as soon as the joint resolution annexing Texas passed the U.S. Congress, would set the Mexican minister in Washington into action towards war. The main factor being the borderline of Texas sat at the West bank of the Rio Grande, when nothing before the December 1836 and Congress of the Republic of Texas claimed that as the boundary. This drawing United States President Polk into action himself. Sending John Slidell to negotiate the boundaries of Texas as well as attempting to purchase New Mexico and California. José María Iglesias a future interim president of Mexico who would write in The other side: or, notes for the history of the war between Mexico and the United States; written in Mexico that reasons why Mexico would lose one third of its territory was because Mexico’s weakness from civil wars and foreign leadership as well as Mexico should have known that The United States desire to control almost the whole continent. As Slidell was returning Mexican president Jose Joaquin response to Polk. General Zachary Taylor was already in position with his dragoons to force action by Mariano Arista’s cavalry. On May 9th Taylor reported to Washington that 16 men were dead because they had been attacked by the Mexican’s thus forcing the hands of Congress to declare war against Mexico. Sam Chamberlain watercolor paintings depict that first charge the Taylors dragoons would lead against Mexico. Sam