Catechism of the Catholic Church §1898 — excerpt
Every human community needs an authority to govern it. The foundation of such authority lies in human nature. It is necessary for the unity of the state.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: Leo XIII, Immortale Dei · Diuturnum illud