Question 111 of 128

Why did the United States enter the Vietnam War?

Official USCIS answers

To stop the spread of communism

Why this is the answer

The United States entered the Vietnam War during the Cold War. It feared that communism would spread through Southeast Asia, so it supported South Vietnam to stop that spread.

💡 Memory tip: Remember: Vietnam was a Cold War fight to contain communism.

Could you say it out loud to an officer?

Practice with the real rules: 20 questions, pass with 12.

Take a free mock test

← 110 112 →

More from Recent American History and Other Important Historical Information

100. Name one war fought by the United States in the 1900s.
101. Why did the United States enter World War I?
102. When did all women get the right to vote?
103. What was the Great Depression?
104. When did the Great Depression start?
105. Who was president during the Great Depression and World War II?

Source: USCIS, 128 Civics Questions and Answers (2025 version), M-1778.