wars u.s. has been involved in?
['The Revolutionary War (1775-1783)', 'War of 1812 (1812-1815)', 'Mexican - American War (1846-1848)', 'American Civil War (1861–1865)', 'Spanish-American War (1898)', 'World War I (1914-1918)', 'World War II (1939-1945)', 'Korean War (1950-1953)']