A recent conversation precipitated this post. It was about the Papal States, on why the Popes at the time fought so hard to keep temporal power (as if it was only about power). From their point of view at the time, to relinquish temporal control would have put the ministry of the Church itself in jeopardy, tinging it with Nationalism, Liberalism, and Republicanism. It was indeed a just concern: Josephism in Austria, Febronionism in Germany, Gallicanism in France. Pio Nono worried that they would eventually try to make the Papacy nothing more than chaplain for the House of Savoy, instead of the Vicar of Christ for all nations. His words below summed up his mindset:
For if the Roman Pontiff were subject to the sway of another ruler, but no longer possessed civil power, neither his position nor the acts of the Apostolic ministry would be exempt from the authority of the other ruler. This ruler could be either a heretic or a persecutor of the Church or constantly at war with other rulers. (Pius IX: On the Pontifical States)
Before anything else, it was about Justice. The Papal States (or officially, the Patrimony of St. Peter) belonged to the Church and She had not agreed to give them up.
They were stolen!… and in a violent manner.
Viva il Papa Re!