The position that the See of Peter is vacant — that the men elected as pope since Vatican II (the cut-off varies by group) are not true popes. Distinct from the SSPX's position, which recognizes the reigning pope while resisting parts of Vatican II; groups such as the SSPV milieu and the CMRI are sedevacantist. First systematically published by Fr. Joaquín Sáenz y Arriaga in the early 1970s.[1]