Why was the north Atlantic treaty organization formed in 1949

The answer is to protect against an aggressive Soviet Union in Europe

The North Atlantic Treaty Organization, NATO, is an international organization established in 1949 with the aim of collaborating in defense in the political, economic and military fields. It was born as a result of an agreement called the North Atlantic Treaty that was signed in Washington DC on April 4, 1949. The signatory countries were those of the Treaty of Brussels (Belgium, France, Luxembourg, Netherlands and the United Kingdom), the United States and Canada, as well as five other Western European countries invited to participate (Denmark, Italy, Iceland, Norway and Portugal). It was designed to be a security guarantee in the states of Western Europe to the Soviet Union and its allies. The Warsaw Pact was created later in 1955 to counter NATO after the admission and possible rearmament of the Federal Republic of Germany. As was the case with the Cold War, NATO forces acted only as a deterrent. Following the disintegration of the Soviet Union, NATO has reformulated its goals and activities, focusing on the security of the entire Northern Hemisphere.