The church, moreover, has always recognized the distinction of
the two powers, and although the Pope owes to the fact that he is
chief of the spiritual society, his temporal principality, no
theologian or canonist of the slightest respectability would
argue that he derives his rights as temporal sovereign from his
rights as pontiff. His rights as pontiff depend on the express
appointment of God; his rights as temporal prince are derived
from the same source from which other princes derive their
rights, and are held by the same tenure. Hence canonists have
maintained that the subjects of other states may even engage in
war with the Pope as prince, without breach of their fidelity to
him as pontiff or supreme visible head of the church.

The church not only distinguishes between the two powers, but
recognizes as legitimate, governments that manifestly do not
derive from God through her. St. Paul enjoins obedience to the
Roman emperors for conscience' sake, and the church teaches that
infidels and heretics may have legitimate government; and if she
has ever denied the right of any infidel or heretical prince, it
has been on the ground that the constitution and laws of his
principality require him to profess and protect the Catholic
faith. She tolerates resistance in a non-Catholic state no more
than in a Catholic state to the prince; and if she has not
condemned and cut off from her communion the Catholics who in our
struggle have joined the Secessionists and fought in their ranks
against the United States, it is because the prevalence of the
doctrine of State sovereignty has seemed to leave a reasonable
doubt whether they were really rebels fighting against their
legitimate sovereign or not.