How about dishing out some excommunications against prominent Liberal "Catholics"?
By their deliberate stepping outside the norms of Catholic life, these individuals have, to all intents and purposes, excommunicated themselves. When the Church makes an official pronouncement of Excommunication, she is merely ratifying their deliberate choice. The Church does not have to make an "official" ruling regarding one's position outside the Church in order for it to be a de facto excommunication.
(no punishment, no crime)