What event triggered the us to issue the truman doctrine

What is the main idea of this excerpt? 1.1.3

How did the theory of social darwinism impact immigrants? it inspired in the immigrants pride that they were able to survive the harsh conditions of their home countries to come to the united states. it demonstrated that immigrants were the most suitable candidates for factory work because they were the most likely to immigrate to rural areas. it encouraged assimilation of immigrants into the american culture through education that involved courses in english and american food and clothing. it provided new american immigrants with a clearly defined social support system to ensure that basic nutritional, educational, employment, and health care needs were met.

Congress could only request money and had no power to tax; each state made its own money; there was no national court system. which one of these weaknesses do you believe was the most important to correct?