I think traditionalist-minded folks can get bogged down with the technicalities of the Msgr Perl letters, and there are several of them, because of nuances related to fulfilling the Sunday obligation and other particular issues. My approach to this issue is simply this: 1. Canon law defines what " schism " is: "Heresy is the obstinate denial or obstinate doubt after the reception of baptism of some truth which is to be believed by divine and Catholic faith; apostasy is the total repudiation of the Christian faith; schism is the refusal of submission to the Supreme Pontiff or of communion with the members of the Church subject to him ." (CIC, 751 ). 2. Schism is incurred " latae sententiae ", that is to say, automatically by the very act of schism, without a need for declaration from the ecclesiastical authority: "An apostate from the faith, a heretic or a schismatic incurs a latae sententiae excommunication " (CIC, 1364 ). 3. The SSPX, in various...