I don't see how anyone could meaningfully say for sure whether Lefebvre would or wouldn't be a Sedevacantist if he was alive today. THere are just way too many variables to say for sure. I think in some ways the case for Sedevacantism (which I do not hold to) is stronger than it was in '88, but in other ways its weaker. John Paul II was not as anti-Catholic as Francis when you look at his own statements, but he was *far* more anti Latin mass at the time.
As far as what Williamson says, he clearly thinks that Francis' papacy *could* be invalid. I have no idea why anyone's bothering to object to the fact that he said that. That's a logically separate issue from insisting on una cuм. I actually think its completely consistent to say that the Church *could* declare the see vacant, and yet still say its schismatic to act as though its anything but occupied *until* the Church makes said declaration. I don't think its right, but I think its valid.
The biggest thing I don't get about this whole thing, and I realize saying this is going to probably upset some people, but I don't see how the SSPX Resistance acts as though the seat is occupied. TBH, if the seat is probably or definitely occupied, Bishop Fellay's approach (at least from what I understand of it) seems to make more sense. We won't celebrate the Novus Ordo, we won't condone it, but we want to be in communion with the Church as long as *we* are not being forced to compromise. By contrast, the Resistance line seems to be much more "we won't be in communion with compromisers.... yet we still think Francis is the Pope".... which doesn't make much sense to me. Its one thing to disobey one's hierarchical superior if he demands you compromise on your faith, but its quite another thing to do so because he tolerates people you think should be excommunicated (to be fair many of them should be) and such. I suppose I could make sense of a position that says "he's probably not pope, but we'll pray for him just in case he is" but that doesn't seem to be the SSPX-Resistance line either.
It seems to me that Williamson prays for the pope, but in other ways acts as though the seat is vacant. Does he actually obey the pope in any way? Does he even want to be in communion with him? Isn't that why the SSPX Resistance separated from the SSPX?
Of course, you could point out that Lefebvre did the same thing. But that seems different to me for one big reason. The Tridentine Mass was in imminent danger of eradication. There wasn't even, as far as I know, *such thing* as the indult, until after Lefebvre's consecrations (sure seems to me like Lefebvre's consecrations forced Rome to the bargaining table.) When you're facing the imminent eradication of the Tridentine Mass, and very possibly any real episcopal resistance to modernism, disobeying your legitimate hierarch seems like a reasonable thing to do. From Williamson, it does seem like a practical belief that the See is Vacant (and thus, wanting nothing to do with it.)
What am I missing here?