It was an American foreign policy proposed by U.S. President Harry Truman. Its purpose was to counter Soviet geopolitical influence. Not by direct military intervention, but by financial aid to support the economy and militaries of the countries involved.
This doctrine leads to the creation of NATO and its often dated by historians as the beginning of the Cold War.
“Pull” factors included encouraging reports of good wages and living conditions that spread by word of mouth and that appeared in African American newspapers.