29 There is no doubt that in the sphere of politics ample matter may exist for legitimate difference of opinion, and that, the single reserve being made of the rights of justice and truth, all may strive to bring into actual working the ideas believed likely to be more conducive than others to the general welfare. But to attempt to involve the Church in party strife, and seek to bring her support to bear against those who take opposite views is only worthy of partisans. Religion should, on the contrary, be accounted by every one as holy and inviolate; nay, in the public order itself of States-which cannot be severed from the laws influencing morals and from religious duties-it is always urgent, and indeed the main preoccupation, to take thought how best to consult the interests of Catholicism. Wherever these appear by reason of the efforts of adversaries to be in danger, all differences of opinion among Catholics should forthwith cease, so that, like thoughts and counsels prevailing, they may hasten to the aid of religion, the general and supreme good, to which all else should be referred. We think it well to treat this matter somewhat more in detail.
Source: Sapientiae Christianae (Vatican.va)