The passage is from President Harry Truman’s explanation of the Truman Doctrine. Totalitarian regimes imposed on free peoples, by direct or indirect aggression, undermine the foundations of international peace and hence the security of the United States. . . .

If we falter in our leadership, we may endanger the peace of the world.

–President Harry Truman,
March 12, 1947

Based on the passage, which statement best explains Truman’s position?

The world needed to resist taking action against totalitarian regimes.
Countries needed to promote peace by joining the United Nations.
The United States needed to lead the fight against the spread of communism.
The United Nations needed to take action to protect peace in the world.