I think YWN also ran a halachic discussion about this. I understood this as: lying is forbidden to non-Jews and while you can acknowledge this guy and rely on his vote, you should try to find other partners when looking for political allies.
On the positive side, this guy may have a been a Berdichever chosid: look, how openly he admits all his aveiros. On the negative side, this seems to be part of the modern trend when all aveiros are not just tolerated in private or overlooked with understanding that “everyone is human”, but proudly paraded in front of the public.
Not only Dems, but Reps should have found this during the primary. American system rightfully does not criminalize such behavior but presumes that open public discourse will deal with such cases. If this is a one-off miss that will warn people that is fine, but not if the next guy will point to this one as a precedent.