Other influential writers in the 1970s include Pierre Clastres, who explains in his books on the Guayaki tribe in Paraguay that "primitive societies" actively oppose the institution of the state. These stateless societies are not less evolved than societies with states, but chose to conjure the institution of authority as a separate function from society. The leader is only a spokesperson for the group when it has to deal with other groups ("international relations") but has no inside authority, and may be violently removed if he attempts to abuse this position.