In his inaugural address, President John F. Kennedy exhorted the nation to remember its heritage of freedom. He reminded Americans that they are the heirs of the American Revolution. Because of that heritage of suffering and sacrifice, Kennedy believed that America had a special purpose on earth.
Essentially, Kennedy wanted Americans to focus on preserving human freedoms at home and help other countries do the same. We get the idea that Kennedy wanted to export American-style democracy to the rest of the world.
We must remember that Kennedy made his speech in the context of the Cold War and at the height of the Berlin Crisis (1958–1961). The two "sides" referenced in his speech are the US and the Soviet Union. He also talks about the need to leverage science for the good of mankind rather than the proliferation of weapons for its destruction.
Kennedy's speech was seen as an exhortation to peace, and he devoted time to both domestic and international concerns. Meanwhile, in his address before Congress in 1947, President Harry S. Truman also focused on the idea of freedom. However, he specifically highlighted the need for foreign aid in aiding the cause of freedom around the world.
Truman asked for economic and military assistance for Turkey and Greece, citing the challenges faced by both countries. It's worth considering how President Truman couched the terms of his request: as a means of exporting American-style freedoms to the rest of the world. He cited the need to aid Greece in fighting the communist revolutionaries that threatened the country's sovereignty. He also reiterated that Turkey was central to stability in the Middle East.