A) During the Cold War, the American governments foreign policy revolved around the concept of stopping the spread of communism on a global scale. However, after the Soviet Union fell and many of their satellite nations became independent, the US government had to adapt a different foreign policy. This new foreign policy would be extremely complex, as they had to deal with genocide (in countries like Bosnia and Herzegovina, and Rwanda), invasions (like Iraq invading Kuwait), and dealing with the acquisition of weapons of mass destruction by potentially dangerous groups (like Al Qaeda and Isis).
B) The US government has responded to this trend by continually being involved in foreign affairs. The US has helped in providing troops, financial aid, and organization to countries that were destroyed by warfare or harmful radical groups. As times change, America will continue this pattern of involvement in order to protect the rights of individuals all over the world.