How did Europe move towards union?

The reason why Europe moves towards the union

First, the European people, who have gradually entered the "golden age", have come to a unanimous conclusion from the painful historical lessons and harsh reality: in order to get rid of the threat of bloody conflicts in Europe, ease national hatred and prevent the recurrence of historical tragedies, it is necessary to reorganize Europe's economic, social and political life. Second, after World War II, the influence of the United States and the Soviet Union in Europe expanded sharply, and the political and economic status of European countries declined. Only by uniting can we re-establish a new image of Europe. Third, with the development of science and technology and production, international competition is becoming more and more fierce, while there are many countries in Western Europe, which have the problems of narrow domestic market and shortage of production resources. Only by moving towards alliance can we complement each other's advantages and benefit the common development of all countries. Fourth, Europe has the same cultural heritage and psychological identity.