In theoryat leastthe concept of collective security and neutrality cannot coexist. In practice, however, both the League and the United Nations had left several loopholes for war and neutrality, consequently the rules governing the latter are still considered applicable in international law. Neutrality is a policy adopted by a State unilaterally in face of a particular war and for no specified period. Thus, Ireland and Sweden during World War II had chosen to remain outside the conflict. She was a member of the League of Nations, and joined also the United Nations.
Neutralization is the outcome of international agreement.
Belgium, for example, was neutralized by the Powers in 1831 on their own initiative and without her request. Once a member of the League of Nations, Switzerland now holds that her neutrality is incompatible with membership in the United Nations. Both are members of the United Nations. Austria also is a member of the European Free Trade Association and of the Council of Europe, in spite of strong criticism from the Communist side. By adhering to this policy, and occasionally formalizing it in the legal sense through declarations of neutrality, the USA aimed at maintaining freedom of trade with all nations whether in peace or war, without renouncing the right to make war when that was in her interest.