7 But, though this opinion is to be avoided, the contrary error must likewise be shunned of those who identify religion with some one political party and confound these together to such a degree as to look on all of another party as undeserving any longer of the name of Catholic. This is an intrusion of political factions into the August realm of the Church; it is an attempt to break the union of brothers, and to open the gate and give access to a multitude of grievous troubles.
Source: Cum Multa (Vatican.va)