Il Fermo Proposito §18

¹⁸ These civil rights are of various kinds, even to the extent of directly participating in the political life of the country by representing the people in the legislative halls. Most serious reasons, however, dissuade Us, Venerable Brethren, from departing from that norm which Our Predecessor, Leo XIII, of blessed memory, decreed during his Pontificate. According to his decree it was universally forbidden in Italy for Catholics to participate in the legislative power. Other reasons equally grave, however, founded upon the supreme good of society which must be preserved at all costs demand that in particular cases a dispensation from the law be granted especially when you, Venerable Brethren, recognize the strict necessity of it for the good of souls and the interest of your churches, and you request such a dispensation.