" [Archbishop Lefebvre's excommunication] may be compared with the excommunications that popes in former times pronounced on their political enemies, sentences which were formally valid but which nobody today would regard as having moral force. In fact its weight is less, for the excommunication came not from a merely secular policy but from one aimed at excluding tradition from the Church or obliging it to compromise with false principles. "

― H.J.A. Sire , Phoenix from the Ashes: The Making, Unmaking, and Restoration of Catholic Tradition