The Second Wold War was the most lethal conflict in the world's history. Many countries, not just the U.S., believed that if more countries stood up to Nazi Germany in the 30s when Germany was gaining power, the war's cost may have been significantly less. After the war, the United States and western Europe formed NATO, or the North Atlantic Treaty Organization. The United States knew that they could no longer become isolationist because of the high standing they were thrust into after the war. The United States was virtually unscathed by the war, and became the number one world power. People did fear the the United States would constantly be at war due to "policing" the other countries of the world. There really were no alternatives to this, the United States needed to help out its former allies.