Tecumseh was a tribal leader who thought all Native Americans needed to get together to force US to stop its expansion. Together the Native Americans were strong enough that US would stop to avoid an armed conflict.
The Spanish-American War of 1898 settled the status of the United States as a Pacific power. U.S. success in the war allowed a peace treaty that compelled the Spanish to resign claims on Cuba, and to cede sovereignty over Guam, Puerto Rico, and the Philippines to the United States. During the conflict, the United States annexed the independent state of Hawaii as well. Therefore, the war enabled the United States to secure its power in the Caribbean region and to seek its economic interests in Asia.
Any war effects the economy. War means you have to pay for weapons, ammo, etc. Not to mention the cost of training all the soldiers and producing tools of war (Such as cannons). This war effected the economy very badly.
Racism blocked migrant workers
Territory in the New World
