The title of this post should be understood properly. In fact, a nation -- not in the ridiculous politically correct sense of "all holders of the citizenship of a certain government" -- but in the real sense of "all people who want to be the citizens of a certain government or would-be government, and don't want the others to be its citizens" -- this is a very important concept explaining the present-day world's politics.
It is just that nations exist at best in indifference, at worst in opposition or enmity to each other, and nothing unites them. Except for Jew-hatred, as we have amply seen.
The United Nations is a dangerous vehicle for legitimizing things that cannot be legitimized or justified on any other grounds. The United Nations Organization should be delegitimized, defunded, and abolished.