The doctrine of Papal infallibility was itself issued as an ex cathedra doctrine, and other administrative points have in the past been expressed as matters of doctrine and faith. Lots of them, in fact. Look at Execrabilis, look at bulls that had absolutely nothing to do with the faith like Dudum siquidem. Popes have also used plenary powers to dissolve unsanctioned meetings of cardinals and bishops (cf. the background on Execrabilis and the Council of Basel).
As any good lawyer will tell you, the trick is simply to reframe the power struggle as a item of Christian faith. If a faction of cardinals is doing something the Pope doesn't like, he just needs to disarm them in a way that threatens their ability to continue their office if they don't desist.
And besides, he can always pack the College of Cardinals with hundreds of new cardinals of his own choosing, and get that body to enact all of his reforms.
ἡ δὲ κἀκ τριῶν τρυπημάτων ἐργαζομένη ἐνεκάλει τῇ φύσει, δυσφορουμένη, ὅτι δὴ μὴ καὶ τοὺς τιτθοὺς αὐτῇ εὐρύτερον ἢ νῦν εἰσι τρυπώη, ὅπως καὶ ἄλλην ἐνταῦθα μίξιν ἐπιτεχνᾶσθαι δυνατὴ εἴη. – Procopius
Ummaka qinnassa nīk!
*MySmiley*
