Nice Idea, But It's Not That Simple
This is pure speculation, but I'm guessing Joe Murray isn't Catholic, otherwise he would know that public excommunications by the Church are rare and seem to only occur when a schism on the scale of Martin Luther or Archbishop Lefebvre is being promoted. Also, a Catholic essentially excommunicates himself when he knowingly refuses to repent from a grave or mortal sin. Nice sentiment, though.
For too long Christians in positions of authority, particularly those proclaiming membership in the communion of the Catholic Church, have separated their Catholic obligations from their public responsibilities. Justice Kennedy celebrates homosexual sodomy, Senator Ted Kennedy advocates for increased abortion rights, and the list goes on and on. It is now time for the Catholic Church to stand up and defend the faith. It is time for the Church to excommunicate such cafeteria Catholics from communion with the Church -- and it should start with Justice Kennedy.