It is equally clear that, in insisting upon one definite principle in all government, the Church has at no time understood that it could be obtained only by particular political forms. She attends to the substance, not to the form, in politics. At various times she has successively promoted monarchy, aristocracy, and democracy; and at various times she has been betrayed by each. The three fundamental forms of all government are founded on the nature of things. Sovereignty must reside with an individual, or with a minority, or with the majority. But there are seasons and circumstances where one or the other is impossible, where one or the other is necessary; and in a growing nation they cannot always remain in the same relative proportions. Christianity could neither produce nor abolish them. They are all compatible with liberty and religion, and are all liable to diverge into tyranny by the exclusive exaggeration of their principle. It is this exaggeration that has ever been the great danger to religion and to liberty, and the object of constant resistance, the source of constant suffering for the Church.
Christianity introduced no new forms of government, but a new spirit, which totally transformed the old ones. The difference between a Christian and a pagan monarchy, or between a Christian and a rationalist democracy, is as great, politically, as that between a monarchy and a republic. The Government of Athens more nearly resembled that of Persia than that of any Christian republic, however democratic. If political theorists had attended more to the experience of the Christian Ages, the Church and the State would have been spared many calamities. Unfortunately, it has long been the common practice to recur to the authority of the Greeks and the Jews. The example of both was equally dangerous; for in the Jewish as in the Gentile world, political and religious obligations were made to coincide; in both, therefore,--in the theocracy of the Jews as in the [Greek: politeia] of the Greeks,--the State was absolute. Now it is the great object of the Church, by keeping the two spheres permanently distinct,--by rendering to Cæsar the things that are Cæsar's, and to God the things that are God's--to make all absolutism, of whatever kind, impossible.