In two words - Civil War.
Having the Mexican Cession to divide up between slave states and free states aggravated the bickering that had been going on for at least 30 years between North and South - - though
the slavery issue was a thorn in the American side at the Constitutional convention in 1787 as well.
Just had a history grad school course on the American Civil War, and the general consensus from the reading was that the Mexican Cession was one of the final straws that led to the break up of the Union in 1860-61. The repercussions of the Civil War are still being felt today - though it is diminishing finally.
What are 5 influences Mexico has made on the United States? - - - California, New Mexico, Arizona, Nevada, Utah, and one extra - - Colorado.
Cultural contributions are many - especially in the states mentioned above. Most common nationwide - Mexican retaurants - - the cuisine.
