The Pope and the President of the United States are in a war of words that would not have surprised medieval popes or Holy Roman Emperors. The division between the secular and the spiritual power has been debated over centuries, with both sides at times claiming complete authority, but neither ever achieving it for very long.
Papal claims to temporal authority reached their apogee under Pope Boniface VIII, in his papal bull Unam Sanctam. This decree stated that there was no salvation outside the Church, that those who resisted the Church, of which the Pope was sole and absolute head, resisted God, and so the temporal authority must eventually submit to the spiritual, i.e. to Pope Boniface VIII. In case of any doubt, it concluded by declaring that “we declare, we proclaim, we define that it is absolutely necessary for salvation that every human creature be subject to the Roman pontiff”.
Sadly for Boniface, this bull was not well received, and he was lucky to escape alive after the Outrage of Anagni, which was carried out by Philip IV of France’s supporters, who held the Pope captive without food or drink for three days. He died, back in Rome, just over a month later.
The truth was that the papacy could not enforce its temporal claims, so their theological accuracy, or otherwise, was merely academic. The ‘two swords’, referred to in Luke 22:38, that were the subject of so much scholastic debate, could not both be effectively wielded by the Pope.
