I have just read all the Canon law sections pointed to from this thread, and the section that I think is most relevant to the topic at hand is Canon 1369:
“A person who in a public show or speech, in published writing, or in other uses of the instruments of social communication utters blasphemy, gravely injures good morals, expresses insults, or excites hatred or contempt against religion or the Church is to be punished with a just penalty.”
So is our debate perhaps about what is the just penalty? I know that you attached the caveat to your “parking ticket analogy” that you are not equating a parking ticket with support for abortion, but really, that’s exactly what it looks like. I believe that Canon 1369 does empower a bishop to impose an excommunication on a pro-abortion politician, (after the appropriate judicial and fraternal steps have been taken). I see supporting abortion to be a very grave matter, and so the gap in justice (if there is one) of imposing an excommunication for legislatively supporting abortion is radically smaller than the gap in justice of imposing the death penalty or life imprisonment for a parking ticket.