The problem with an accusation of Modernism is that Modernism is DESIGNED to be subtle. I have no doubt that Francis is a Modernist, but “manifest” heresy would have to be something like Arianism, or denial of the Real Presence—something along those lines. And to be “manifest,” the heresy would have to appear in some kind of document. To have heretical opinions, which I think Francis does, is not the same as being a “heretic.” A heretic is contumacious. A heretic campaigns against the Church.
Charles Curran and the other dissenters against Humanae Vitae were heretics. Richard McBrien is a heretic.
Don’t get me wrong. I am not saying Francis is a good Pope. I’m saying he hasn’t done anything that FORCES honest people to admit that he’s not Pope.
If the Synod comes out for Communion for adulterers, and Francis ratifies that conclusion, THEN he would be a manifest heretic.