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Someone who knows the rule could clarify this, but as I recall, there are certain sins that cannot be absolved by a priest but the penitent is referred to confess it (or them) to the local bishop. It seems to me that one such sin would be apostasy or formal heresy, especially if it was public and committed by a well-known person.
If this is correct, then a public figure like a congressman saying that it doesn't matter what church you're in you can be saved without the Catholic Church, then he would have to confess to his local bishop.
Of course, in these days, the local bishop might not have much to say about it, but then again, there may be a few around who could do some good.
I can't help but imagine how Ambrose Moran might counsel a penitent on this.
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