67 Undoubtedly, that formation should aim as well at the preparation of youth to fulfill with intelligent understanding and pride those offices of a noble patriotism which give to one's earthly fatherland all due measure of love, self-devotion and service. But, on the other hand, a formation which forgot or, worse still, deliberately neglected to direct the eyes and hearts of youth to the heavenly country would be an injustice to youth, an injustice against the inalienable duties and rights of the Christian family and an excess to which a check must be opposed, in the interests even of the people and of the State itself.
Source: Summi Pontificatus (Vatican.va)