People extremely critical of the institution of the United Nations do not understand its conceptual necessity. Usually concerns regarding the United Nations are about sovereignty/autonomy of their independent nation. This represents a fundamental misunderstanding of the institution, as it is not a governing power, or “super nation”, but rather an intermediary for autonomous and sovereign nations.
The rationale, at least as presented by prominent Western political philosophers, and completed by Immanuel Kant in his work Perpetual Peace, is that a there is a universal moral law, that all persons have certain rights. To ensure these rights we implement constitutions, implementing means to operate societies, and have representatives to enact government to ensure these rights. We require representatives, and thus a republican government, for this reason: nowhere in democracy is a principled moral basis, and rather just the arbitrary will of the majority; this gives us the common political and legal saying, that we have a government of “majority rule with minority rights”. We follow a government because of a social contract, an agreement to allow the rights of all to be protected by allowing ourselves to be subjected to a government to implement these protections. Contracts function as an agreement that respects the rights of all participants. Contracts, or treaties, between governments then are agreements to mutually respect the rights of the participants, often as the individual governments are operating to serve the rights of its constituents. Governments, laws, and thus courts function to mitigate any failures of respecting the mutual rights agreement established in the contract. The question then becomes: who, or what, is to mitigate any possible failures in international agreements? This gives us the need to have the United Nations as the international mitigation of any treaties, or contracts; also, as an institution of rights, its goal is to work to guarantee the rights of all; most important its member nations, in the form of their being protected in treaties as well their autonomy. So national sovereignty, or autonomy, is maintained, while at the same time rights are protected.
What people are doing, then, when wanting to act without the United Nations, is to undermine the principles of their government and their own human rights. It’s not that we shouldn’t be concerned about our nation’s sovereignty, but instead that we should not confuse an institution ensuring mutual respect to an institution taking away national autonomy and freedom.