CathInfo.com

My belief is that because the salvation doctrine has been under a cloud for so long, I cannot judge those who hold various loopholes concerning it. Nevertheless, I must still insist that once a person realizes that the dogma is defined ex cathedra, then they must hold it to be Catholic.

If they deny it outright, as did Archbishop Cushing when he said that the doctrine is “nonsense,” then that is a mortal sin.  Does denying it place one “outside the Church” as a formal heretic? 

If one holds, even privately, that the Church is “wrong” and that this definition, or any other, is not infallible, then, yes, in the internal forum they are no longer in the Church. In the external forum, they can believe themselves to be Catholic, even insist that they are “Catholic,” but that is a contradiction. When it comes to this particular doctrine, those who make a point of opposing it are almost always practicing Catholics who are embarrassed by its literal clarity.  So, they try to water it down by expanding the definition of “Church,” by applying baptism of  desire to anyone who is sincere, or by holding that no one can be punished for not believing what they had no way of knowing, i.e., invincible ignorance.  These kinds of objections do not make one a “formal” heretic. But they are in material heresy.  Only God can judge their culpability.  It becomes a much more serious obligation to embrace the doctrine as defined when someone is shown the infallible definitions and one admits that the teaching is de fide ex cathedra.   

American clergy seem to have a more difficult time with the doctrine.  When I question Europeans about it, they are surprised that Father Feeney was persecuted for defending it.  In fact, I know a Frenchman whose SSPX priest introduced him to "Feeneyism" go figure.