In his classic work, Secession, Lee S. Buchheit puts forward two main criteria for the group: (1) The subjective self-perception of the group needs to be distinct from the others; and (2) the group must have objective characteristics which distinguish it from the ambient population." Examples of such characteristics include "elements of a religious, historic, geographic, ethnologic, economic, linguistic, and racial character." At the same time, it is evident that these criteria, even when present, are not "sufficient" by themselves. Moreover, the inability to meet both of these criteria. sometimes has not been an obstacle to self-determination. The United States at the end of the 18th century, for example, met only one objective criteria, geography, necessary for it to secede from the British Empire and to self-determine. Nonetheless, it did secede.
✔A quick survey of international practice surrounding self-determination referenda
organized in the past 20 years (Lineira and Cetrà 2015; Mendez and Germann 2016) may be informative. 🔴Twenty-six out of 55 independence referenda have been held without the consent of the parent state. More than half of them (18 out of 26) led to the emergence of a new state, which were all later recognized by all EU member states