What was the purpose of the Truman Doctrine?

The main purpose of the Truman Doctrine was to prevent the spread of communism.

On March 27, 1947, Harry Truman gave a speech known today as the Truman Doctrine. Within this speech, he talked about how he wanted to help countries like Greece and Turkey stop the spread of communism.

The United Kingdom did not want to help Greece and Turkey any further, as they had no money to spare after World War II, so Harry Truman decided that the United States would help them stop the spread of communism.

i believe the answer is:

-   william jennings bryan is a democrat while mckinley was a republican

at that time, the segment of population that choose for democratic party were the voters with low economic background and vice versa

- william jennings has support of populists and wants to have inflation to farmers while mckinley has support of bankers and businessmen , doesn't want inflation

the fixed value of gold make the large business able to stack up their gold without   being worried that it would devaluated.

- william jennings supported the silver standard while mckinley supported the gold standard

according to jenning, using other metal beside gold could the poor people to have more purchasing power and them advance in the society.

i also think he is correct. i believe they came to washington to protest their rights.