In the views of S.E. Finer, in order to define a state (city-state, nation-state, etc.), it must possess five characteristics:

Note: Pre-modern states usually only possessed three out of five, while modern states possess all five; though, it may only be to a slight degree.

1. The territorial defined population recognizes a supreme form of government.
2. This government is served by civil servants, who make decisions concerning the state, and a military force that protects the state.
3. The state is recognized by other states as independent.
4. The population of the state forms a community, or a sense of nationality.
5. The members of the community mutually participate in duties and benefits.

Source: The History of Government, by: S.E. Finer