Sedeprivationism is a doctrinal position within Traditionalist Catholicism which holds that the current occupant of the Holy See is a duly-elected pope, but lacks the authority and ability to teach or to govern unless he recants the changes brought by the Second Vatican Council.[1] The doctrine asserts that since this council, occupants of the See of Peter are popes materialiter sed non formaliter, that is "materially but not formally". As such, sedeprivationists teach that Pope John XXIII, Pope Paul VI, Pope John Paul I, Pope John Paul II, Pope Benedict XVI, and Pope Francis have not attained fullness of the papacy.[2]
Sedeprivationism is held by some traditionalist Catholic groups such as the Istituto Mater Boni Consilii and Orthodox Roman Catholic Movement, among others. The doctrine of Sedeprivationism traces its origin to the Thesis of Cassiciacum of the Dominican Catholic theologian Michel-Louis Guérard des Lauriers.[3]