Read this: Like his predecessor Pius XII, Paul VI put much emphasis on the dialogue with all nations of the world through establishing diplomatic relations. The number of foreign embassies accredited to the Vatican doubled during his pontificate. This was a reflection of a new understanding between Church and State, which had been formulated first by Pius XI and Pius XII but decreed by Vatican II. The pastoral constitution Gaudium et spes stated that the Catholic Church is not bound to any form of government and willing to cooperate with all forms. The Church maintained its right to select bishops on its own without any interference by the State.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What document states that the Catholic church is not subject to any particlar government?
Gaudium et spes