Final answer:
The Cold War was a long-standing rivalry between the US and the USSR, starting after WWII and characterized by threats of nuclear conflict, proxy wars, and competition for global supremacy. It started under the leadership of President Harry S. Truman and Premier Joseph Stalin.
Step-by-step explanation:
The Cold War
The Cold War was a prolonged period of geopolitical tension between the United States and the Soviet Union (USSR) and their respective allies, the Western Bloc and the Eastern Bloc, following World War II. This era, extending from the close of World War II in 1945 to the dissolution of the Soviet Union in 1991, was marked by a series of indirect confrontations and competition in the areas of military might, ideological conflict, and global influence.
At the start of the Cold War, the leaders of the US and the USSR were President Harry S. Truman and Premier Joseph Stalin, respectively. Although the conflict never escalated to direct military engagement, known as a "hot" war, it involved various forms of warfare including nuclear arms races, proxy wars, psychological warfare, and competitions for technological and space exploration supremacy.
The iron curtain speech in 1946 by Churchill marked a profound clarification of the divisions in Europe, signaling the commencement of the Cold War period. Unlike traditional wartime engagements, the Cold War did not include actual combat between US and Soviet forces but was rather characterized by Mutually Assured Destruction (M.A.D), technological advancements, and influence exertions upon other nations' political systems through indirect means.