See? No rival claimant to the Chair of Blessed Peter = no justification for schism.
Schism is never justifiable.
You must have seen these quotes, Pax.
F.X. Wernz, P. Vidal: “Finally they cannot be numbered among the schismatics, who refuse to obey the Roman Pontiff because they consider his person to be suspect or doubtfully elected on account of rumours in circulation.” (Ius Canonicuм, 7:398, 1943)
Rev Ignatius Szal: “Nor is there any schism if one merely transgress a papal law for the reason that one considers it too difficult, or if one refuses obedience inasmuch as one suspects the person of the pope or the validity of his election, or if one resists him as the civil head of a state.” (Communication of Catholics with Schismatics, 1948)
De Lugo: “Neither is someone a schismatic for denying his subjection to the Pontiff on the grounds that he has solidly founded [‘probabiliter’] doubts concerning the legitimacy of his election or his power [refers to Sanchez and Palao].” (Disp., De Virt. Fid. Div., disp xxv, sect iii, nn. 35-8)
Nothing in those about a rival claimant.
All of those quotes, and more besides, can be found at this site here:
http://www.catholictradition.org/Tradition/indefectibility.htmFirst Vatican Council, Sess. 4, ch. 2, no. 5 : Therefore, if anyone says that it is not according to the institution of Christ our Lord Himself, that is, by divine law, that St. Peter has perpetual successors in the primacy over the whole Church; or if anyone says that the Roman Pontiff is not the successor of St. Peter in the same primacy: let him be anathema.And yet, you tell me, that for an entire generation, and well into the next generation, there has been no Successor of Blessed Peter?