John McCormick lists the variety of reasons making states integrate each other. What are those reasons?
First, states may be brought together by force, as they were in Europe by Napoleon and Hitler. Second, they may become together out of the need for security in the face of a common external threat, as the members of the North Atlantic Treaty Organization (NATO) did during the Cold War. Third, they may share common values and goals and agree to cooperate or share resources in selected areas, as the Nordic states on transport, education, and passports have. Fourth, they may decide that they can promote peace and improve their quality of life successfully by working together rather than separately, as the members of the United Nations (UN). Interstate relations in Europe were long influenced and driven by the first two motives, but since 1945 there has been a shift to the third and the fourth. In other words, compulsion has been replaced by encouragement. There are still debates about whether the regional integration like in the EU is beneficial or harmful for states taking part in the regional blocks.