He fingered the mound of faggots on which the wooden martyr stood. That's where all of us are standing now, he thought. On the fat kindling of past sins. And some of them are mine. Mine, Adam's, Herod's, Judas's, Hannegan's, mine. Everybody's. Always culminates in the colossus of the State, somehow, drawing about itself the mantle of godhood, being struck down by the wrath of Heaven. Why? We shouted it loudly enough--God's to be obeyed by nations as well as men. Caesar's to be God's policeman, not His plenipotentiary successor, nor His heir. To all ages, all peoples. --"Whoever exalts a race or a State or a particular form of the State or the depositories of power...whoever raises these notions above their standard value and divinizes them to an idolatrous level, distorts and perverts an order of the world planned and created by God....." Where had that come from? Eleventh Pius, he thought, without certainty--eighteen centuries ago. But when Caesar got the means to destroy the world, wasn't he already divinized? Only by the consent of the peopel--same rabble that shouted: "Non habemus regem nisi caesarem," when confronted by Him--God Incarnate, mocked and spat upon. Same rabble that martyred Leibowitz....
From Walter M. Miller, Jr., A Canticle for Leibowitz. The quote in the passage is indeed from Pius XI -- Mit brennender Sorge, 14 March 1937. The full quotation is:
Whoever exalts race, or the people, or the State, or a particular form of State, or the depositories of power, or any other fundamental value of the human community - however necessary and honorable be their function in worldly things - whoever raises these notions above their standard value and divinizes them to an idolatrous level, distorts and perverts an order of the world planned and created by God; he is far from the true faith in God and from the concept of life which that faith upholds.
Unfortunately, it's a truth of which people need continual reminding.