1. Explain how the post-war era became the American Century.

Hello! the answer is pretty long, so just read, copy, and paste!

Explanation:

Following World War II, the United States emerged as one of the two dominant superpowers, along with the the Soviet Union. The U.S. Senate in a bipartisan vote approved U.S. participation in the United Nations (UN), which marked a turn away from the traditional isolationism of the United States and toward increased international involvement. In 1949, the United States, rejecting the long-standing policy of no military alliances in peacetime, formed the North Atlantic Treaty Organization (NATO) alliance, which continues into the 21st century. In response, the Soviets formed the Warsaw Pact of communist states.

In August 1949, the Soviets tested their first nuclear weapon, thereby escalating the risk of warfare. Indeed, the threat of mutually assured destruction prevented both powers from going too far, and resulted in proxy wars, most notably in Korea and Vietnam, in which the two sides did not directly confront each other. Within the United States, the Cold War prompted concerns about Communist influence. The unexpected leapfrogging of U.S. technology by the Soviets in 1957 with Sputnik, the first Earth satellite, began the Space Race, won by the Americans as Apollo 11 landed astronauts on the moon in 1969. The angst about the weaknesses of U.S. education led to large-scale federal support for science education and research.

a system of cooperative federalism emerged, as the powers of the federal government expanded.