Nationalism and isolationism both had major impacts on global conflict. Nationalism, or the belief in a nation's superiority and right to self-determination, led to the formation of alliances and increased tensions between nations as countries sought to protect their interests. Isolationism, or the policy of avoiding involvement in international affairs, contributed to an atmosphere of mistrust and competition between nations, as each sought to protect itself from foreign interference. Both ideals were major factors in the conflicts of the early 20th century, including World War I and II.