After world war ii, many countries believed in the principle of collective security, which means that a nation should recruit allies only in times of crisis nations should not get involved with other countries a nation should deal with its conflicts on its own nations should act together to promote peace

  Nations should act together to promote peace.

Explanation:

  After World War II there was a meeting in San Fransico where 50 governments met with the purpose to develop an intergovernmental organization tasked with maintaining international peace and security and by doing that prevent future wars.

  They all drafted the United Nations charter and it began operation on 24 October of 1945. It succeeded in the ineffective League of Nations created after World War I.

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