Question 110: Why did the United States enter the Korean War?
Official answer
- To stop the spread of communism
Grandpa explains
In 1950 communist North Korea invaded South Korea. The U.S. went to defend the South.
Careful: these are NOT the answer
These are the common mix-ups. The app uses them as traps so you practice.
- Because Japan attacked Pearl Harbor
- To force the Iraqi army from Kuwait
- To win independence from England
Video lesson on this topic: The 1900s and Today
More questions on this topic
- 111Why did the United States enter the Vietnam War?
- 112What did the civil rights movement do?
- 113Martin Luther King, Jr. is famous for many things. Name one. ★
- 114Why did the United States enter the Persian Gulf War?
- 115What major event happened on September 11, 2001 in the United States? ★
- 116Name one U.S. military conflict after the September 11, 2001 attacks.
Official sources:
- USCIS · 128 Civics Questions and Answers (2025 version), M-1778 (09/25) ↗ · checked October 6, 2026
The plain explanation is ours; the official answers are USCIS's, word for word.