Sullivan was and is a conservative Catholic, but is so pro-gay marriage it throws him off balance. I saw him on a panel one time where the other gays wished him dead. I don't understand his flip-flop on the war, but I disagree it's because GW is against gay marriage.
No, he is NOT a conservative Catholic. NO more than John Kerry is. Or Ted Kennedy. Or any "priest" who is violating his vows by sexual relationships, etc.
People lay claim to being "Catholic" even so far as if their parents were, if they went to Catholic school or even if they once sat in a pew.
Andrew Sullivan makes choices in opposition to the Church. He is one of those people who gets mileage out of "being Catholic" but who does not repent of wrong deeds nor renew his life.
Receiving Holy Communion while in a state of mortal sin is condemning of one's soul. Who can say if Sullivan has confessed and repented, but I don't see from his own experiences that he's ever modified his behavior. That tells me there is no repentance. The conclusion is obvious, then.