A pretty impartial analysis of these issues was done by an Israeli historian of Europe named Martin van Creveld in his Rise And Decline Of The State published by Cambridge University Press.
I should also mention that the first modern political parties - by which I mean people forming groups on the basis of ideology and not in terms of political factions based on social status (rich versus poor, my family versus your family, noble versus commoner, etc.) - were in medieval Italy. They were called the Guelphs and the Ghibellines. The Guelfs were supporters of papal rule in Italy and the Ghibellines of imperial rule. Most of these political partisans were citizens of republics that were allied with either the Pope or the Emperor. Many of the pope-supporting Guelfs were highly critical of the Popes and sometimes went to war against them - but their ideology was that they preferred papal influence from Rome rather than foreign imperial influence from Germany. The Ghibellines took the view that the Emperors had historical right through the Lombard monarchy to rule in Italy and that the popes were too weak to prevent the French from dominating Italy (they were right).
The most famous Catholic poem, Dante Alighieri's Divine Comedy was written by a disillusioned Guelph turned quasi-Ghibelline (he thought the solution was finding an Italian-born prince who could be elected Emperor) and much of the poem discusses contemporary events he was involved in.
You are jiggling very faint memories. LOL.
Thx thx.