Topic: after providing a brief background on the Texas revolution, the rise of the concept of Manifest Destiny, and the United States annexation of Texas, discuss the causes, views about, and consequences of the United States War with Mexico, 1846-1848. Do not write a detailed account of the battles in Texas or Mexico. Make certain you answer these questions in your essay: Why did the United States go to war in Mexico? What was the importance of the river boundaries? What role did President James Polks ambitions play? What instructions did he give the US Army prior to the outbreak of the war? What territory did the United States gain? What did citizens of the United States and Mexico think? How did the war impact the Mexicans?