The Expansion

Manifest Destiny

The 19th Century Doctrine that the US had the right and duty to expand throughout the North America continent.

War of Texas Independence

The US was alarmed over the policy Great Britain had toward Texas. They wanted the annexation of Texas but Great Britain did not and contemplated using force to make sure it didn't happen.

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Mexican War

The annexation of Texas in 1845 caused an immediate rupture between the US and Mexico because Mexico claimed Texas as part of its territory.