§1. Unless the statutes provide otherwise, it is for the ecclesiastical authority mentioned in can. 312, §1 to confirm the moderator of a public association elected by the public association itself, install the one presented, or appoint the moderator in his own right. The same ecclesiastical authority also appoints the chaplain or ecclesiastical assistant, after having heard the major officials of the association, when it is expedient.
§2. The norm stated in §1 is also valid for associations which members of religious institutes erect outside their own churches or houses in virtue of apostolic privilege. In associations which members of religious institutes erect in their own church or house, however, the nomination or confirmation of the moderator and chaplain pertains to the superior of the institute, according to the norm of the statutes.
§3. In associations which are not clerical, lay persons are able to exercise the function of moderator. A chaplain or ecclesiastical assistant is not to assume that function unless the statutes provide otherwise.
§4. Those who exercise leadership in political parties are not to be moderators in public associations of the Christian faithful which are ordered directly to the exercise of the apostolate.
Source: Code of Canon Law (Vatican.va)