Use the excerpt to answer the question.

In the excerpt, Truman makes a comparison between which of the following political systems?

A.
monarchy and oligarchy

B.
communism and totalitarianism

C.
democracy and monarchy

D.
democracy and communism

D. democracy and communism

Excerpt from the Truman Doctrine, 1948

To ensure the peaceful development of nations. . . the United States has taken a leading part in establishing the United Nations, The United Nations is designed to make possible lasting freedom and independence for all its members. We shall not realize our objectives, however, unless we are willing to help free peoples to maintain their free institutions and their national integrity against aggressive movements that seek to impose upon them totalitarian regimes. . . . totalitarian regimes . . . undermine the foundations of international peace and hence the security of the United States.

The peoples of a number of countries of the world have recently had totalitarian regimes forced upon them against their will. The Government of the United States has made frequent protests against coercion and intimidation, in violation of the Yalta agreement, in Poland, Rumania, and Bulgaria. I must also state that in a number of other countries there have been similar developments.

At the present moment in world history nearly every nation must choose between alternative ways of life. The choice is too often not a free one.

One way of life is based upon the will of the majority, and is distinguished by free institutions, representative government, free elections, guarantees of individual liberty, freedom of speech and religion, and freedom from political oppression.

The second way of life is based upon the will of a minority forcibly imposed upon the majority. It relies upon terror and oppression, a controlled press and radio; fixed elections, and the suppression of personal freedoms.

I believe that it must be the policy of the United States to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures.

In the excerpt, what is the main idea behind the Truman Doctrine?

The main idea behind the Truman Doctrine is that the United States will provide political, military, and economic assistance to democratic nations under the threat of totalitarian regimes that seek to undermine international peace and security. Truman argued that totalitarian regimes are based on the will of a minority forcibly imposed upon the majority and rely upon terror and oppression while free democratic governments are based upon the will of the majority and distinguished by free institutions, representative government, free elections, guarantees of individual liberty, freedom of speech and religion, and freedom from political oppression. Truman believed that the government of the United States must support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures.

To determine the correct answer, we need to examine the excerpt mentioned. However, since the excerpt has not been provided, I am unable to analyze it and provide a specific answer. To answer this question correctly, please provide the relevant excerpt or any additional information that might help in identifying the political systems being compared.