Which war was fought by the United States in the 1900s?

The United States was involved in multiple significant wars during the 1900s, making the choice that includes all of them accurate. Each of these conflicts—World War I and World War II—was pivotal in shaping global politics and the U.S. role on the world stage.

World War I occurred from 1914 to 1918, with the U.S. entering in 1917. It marked a significant change in U.S. foreign policy, transitioning from isolationism to a more active engagement in global affairs.

World War II followed soon after, from 1939 to 1945, and the U.S. was a critical player after entering the war in 1941 following the attack on Pearl Harbor. This conflict resulted in profound changes worldwide and established the U.S. as one of the leading superpowers.

Additionally, the Korean War, which lasted from 1950 to 1953, was also a significant military engagement for the United States. It was part of the broader context of the Cold War and reflected the U.S. commitment to containing communism.

Therefore, all three wars—Korean War, World War I, and World War II—were fought by the United States in the 1900s,