Actually, the Papal States WERE a stellar example of the Pope as a temporal ruler. When the Italian liberals invaded to "liberate" them, they were quite shocked to find that, instead of oppressed, impoverished slaves yearning for freedom, the people they met were cold toward them and refused to participate in their "elections" to vote out the Pontiff.
The Pope is a temporal as well as a spiritual ruler, in fact, before good ol' Paul VI did away with it, whenever a Pope was crowned they were given the title of "the ruler of the rulers of the world", because no other authority can be higher than that given by Christ Himself to St Peter.
Christ did not give any temporal authority to Peter.