Actually, when one HAS BEEN excommunicated, one may NOT use the adjective "Catholic" in self-reference.
Study Canon 915, btw.
And you have NO IDEA what other provisions were in the Daschle letter, do you? You don't KNOW whether Tommy has been forbidden to partake in the sacraments, do you?
Finally, excommunication is usually self-imposed with paperwork sometimes following.
Check the Canon Law on that, while you're looking at 915.
For specific actions. What specific action earned Daschle excommunication?