Final answer:
Churchill envisioned the United Nations as a foundation for global peace involving a Security Council for peacekeeping and military action if required, and an organization fostering economic and social cooperation.
Step-by-step explanation:
According to Winston Churchill, the role of the United Nations should be to serve as the cornerstone of international peace and stability, structured upon the principles set out in its Charter, with a focus on collective security, peaceful dispute resolution, and multilateral cooperation among sovereign states. Key to this vision was the establishment of a Security Council, including the original Four Policemen (the United States, the United Kingdom, the Soviet Union, and China) plus France, endowed with the power to maintain peace and, if necessary, deploy military forces.
Additionally, Churchill, along with others such as Cordell Hull and Franklin D. Roosevelt, believed that a new, more robust global organization was required to prevent another catastrophic war and support economic and social flourishing post-World War II.