Have they been formally (ferendae sententiae) excommunicated?
If so, wouldn’t they be forbidden from receiving Holy Communion in any diocese they visit?
It's Canon 915. "Illinois Senate President John Cullerton and Speaker of the House Michael J. Madigan,...are not to be admitted to Holy Communion in the Diocese of Springfield in Illinois because they have obstinately persisted in promoting the abominable crime and very grave sin of abortion" (the wording of the June 2 decree.)
Paprockis decree formally instructs priests and deacons in the Diocese of Springfield to refrain from administering the sacrament of the Eucharist to Cullerton and Madigan.