Enotes is a good website that can help you and also answers.com
Freezing Ice into Massachusetts at the time
Question below!
Why did President Johnson believe that it was important for the United States
to win in Vietnam?
Answer:
<em>Hello, There! I'm here to help!</em>
<em>The Correct Answer Is D. He believed in the domino theory.</em>
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Explanation:
Information to backup My Answer!
President Johnson believed that it was most important for the US to win in Vietnam because communists were spread around the world and Australia and the US feared that the domino theory was becoming true.

Hope this helps!