The breakup of the Soviet Union, Yugoslavia, and areas like South Sudan and the self-proclaimed independence of rogue states like ISIS in recent years have brought back into discussion the definition of a nation-state. International law predominantly governs the interaction between states instead of between individuals, organizations, or corporations. Thus, the definition is important not only for international affairs but also to assess jurisdictional questions.
There are generally accepted, though no fixed rules, for the recognition of a nation-state. The acceptance of a nation-state into the community of states provides for customary protocols, rights, and responsibilities in international law. The general characteristics a nation-state requires for international recognition include territory and effective central governance – both acquired legally. In addition to acquiring the control and territory legally, many EU countries and other nations also refuse to grant recognition without the new state complying with the fundamental standards on human rights and respecting legally accepted international frontiers. These latter elements became critical to recognition in the last 25 years and the rise of the EU. Once these elements are met, the nation-state is generally accepted into the community of states, can apply for admission to the UN and multi-national NGOs, and begin to negotiate binding treaties.
This acceptance is generally conveyed by establishing diplomatic relations, the expression of formal recognition by other nations, and the de facto recognition of governing authority. In general, this conveys the protocols under international law. In most cases, it also creates effective estoppel of the recognizing states from then withdrawing recognition. This is generally important when there are breakups – such as the dissolution of the Soviet Union, or wars of national liberation, most recently seen in South Sudan. The original nation-states are effectively estopped from legally asserting sovereignty over the former territories.
The last 100 years have seen the birth and death of many nation-states. The elimination of the colonial power scheme, coupled with the breakup of some nations and the merger of others, created a well-established set of precedent and international law revolving around the recognition and process for birth, merger, secession, and death of a nation-state.