All Catholics must make themselves felt as active elements in daily political life in the countries where they live. They must penetrate, wherever possible, in the administration of civil affairs; must constantly exert the utmost vigilance and energy to prevent the usages of liberty from going beyond the limits fixed by God's law. All Catholics should do all in their power to cause the constitutions of states and legislation to be modeled on the principles of the true Church.
Pope Leo XIIIIt is not the part of prudence to neglect that which antiquity in its long experience has approved and which is also taught by apostolic authority.
Pope Leo XIII