World War II (1941-1945): The United States entered World War II in 1941 after the attack on Pearl Harbor by Japan. The war was fought on a global scale, and the United States played a major role in defeating the Axis powers. The war ended with the surrender of Japan in 1945.
Korean War (1950-1953): The Korean War began in 1950 when North Korea invaded South Korea. The United States led a United Nations force that intervened to support South Korea. The war ended in a stalemate in 1953 with the signing of an armistice agreement.
Vietnam War (1955-1975): The Vietnam War began in the 1950s as a civil conflict between North and South Vietnam. The United States became increasingly involved in the conflict, and by 1965 had committed over 500,000 troops to Vietnam. The war ended in 1975 with the fall of Saigon to North Vietnamese forces.
Gulf War (1990-1991): The Gulf War began in 1990 when Iraq invaded Kuwait. The United States led a coalition of international forces that expelled Iraqi forces from Kuwait. The war ended in 1991 with the liberation of Kuwait.
War in Afghanistan (2001-2021): The War in Afghanistan began in 2001 after the September 11 attacks on the United States. The United States invaded Afghanistan in order to dismantle the al-Qaeda terrorist network and to remove the Taliban government from power. The war lasted for 20 years and ended in 2021 with the withdrawal of American forces from the country.
Iraq War (2003-2011): The Iraq War began in 2003 when the United States invaded Iraq under the pretense that the country possessed weapons of mass destruction. The war lasted for 8 years and ended in 2011 with the withdrawal of American forces from Iraq.