The vast majority of states in the international system, democratic and non-democratic, are multi-ethnic (Gurr 1993). A liberal-democratic multi-ethnic state serves the collective needs of all its citizens regardless of their ethnic affiliation, and citizenship—legally recognized membership in the political structure called a state—is the single criterion for belonging to the state and for granting equal opportunity to all members of the system. Whether a multi-ethnic democratic state should provide group rights above and beyond individual legal equality is an ongoing debate (Gurr & Harff 1994).