The Mexican War (1846-1848) was the result of many factors, not the least of which was westward expansion. Expansionists became interested in the area above the Mexican borderlands, Texas, as well as New Mexico, California and Oregon. By 1835 there were 20, 000 settlers in Texas, many of which were plantation owners who had moved in with their slaves. Texans declared their independence in 1836 and applied for annexation, but President Jackson did not recognize their independence until 1837, just …showed first 75 words of 1815 total…

…showed last 75 words of 1815 total…also gained them the controversy that led straight to the sectional crisis and deadlock, which in turn led eventually to a civil war. So the comment that the American victory was like a dose of arsenic, a slow-acting poison, is a credible one. The poison began its work as early as 1846 with the Wilmot Proviso, and slowly ate its way through the stability of the U.S. until a war was the only possible outcome.