20 Of The Worst Presidential Mistakes In American History, And What Actually Happened

—u/Hrekires

President: Dwight D. Eisenhower

Years in Office: 1953–1961

Preceded by: Harry S. Truman

Succeeded by: John F. Kennedy

What Happened: France had colonized Vietnam (along with Laos and Cambodia) since the mid-19th century, ruling it as part of French Indochina. After World War II, Vietnamese nationalist and communist forces under Ho Chi Minh fought the French for independence. The French defeat at Dien Bien Phu in 1954 marked the end of nearly a century of colonial control. The Geneva Accords that followed divided Vietnam at the 17th parallel — with communist control in the North and a US-backed, anti-communist government forming in the South. The United States, though not a formal signatory to the accords, quickly stepped into the French vacuum.

Under President Eisenhower, US policy fully embraced the domino theory — the belief that if one country fell to communism, others in the region would follow. His administration funneled massive financial and advisory support first to the French, then to the fledgling government of South Vietnam, marking the early militarization of US containment policy.

Washington fundamentally oversimplified regional geopolitics, assuming communist states like the USSR and China formed a unified bloc. This ignored deep nationalist divisions and historical animosities within Asia. Fear of the “domino effect” came to justify support for corrupt or authoritarian regimes across the globe, entrenching US involvement in conflicts like the Korean War (1950–1953) and the Vietnam War (1955–1975) alike.

President: John F. Kennedy

Years in Office: 1961–1963

Preceded by: Dwight D. Eisenhower

Succeeded by: Lyndon B. Johnson

What Happened: President Kennedy dramatically deepened this commitment. Inheriting about 900 advisers from Eisenhower, he expanded the US presence to roughly 16,000 military advisers by late 1963 and introduced Special Forces and counterinsurgency units. He also tacitly supported the 1963 coup that overthrew and assassinated South Vietnamese President Ngo Dinh Diem, further destabilizing the country. By shifting from indirect aid to direct political and military engagement, Kennedy left his successor with a near-irreversible entanglement.