According to Shawʻs textbook International Law (Cambridge University Press) p. 178: there are 4 criteria for being a state (i.e., a country): 1. permanent population (citizenry) 2. a defined territory 3. a government 4. capacity to enter into agreements with other states (i.e. to make treaties). Hawaii had all the criteria in 1898, hence the need for a treaty for annexation, hence the illegality of annexation, hence the kingdom’s continued existence under occupation.