Oh dear. Yes, one has to ignore some of that. Popes have said so many things in the past, that if you tried to apply them all you would go mad.
We have to deal with the here and now, and people don't want a catholic theocracy. Nor should they be forced to submit to one in this world.
That kind of thinking is arrogant and dangerous. Some popes didn't believe in liberty either. Some popes believed in coralling the Jews.
You sound just like that Droelsky. If that is what you believe, turning America into a catholic theocracy, we have more to fear than Islam.
Without a revolution or a mass conversion to catholicism, there will be separation of church and state in this country whether it is an ideal concept or not.
We are informed by the texts of the gospels that in this Church and in its power are two swords; namely, the spiritual and the temporal. For when the Apostles say: 'Behold, here are two swords' [Lk 22:38] that is to say, in the Church, since the Apostles were speaking, the Lord did not reply that there were too many, but sufficient. Certainly the one who denies that the temporal sword is in the power of Peter has not listened well to the word of the Lord commanding: 'Put up thy sword into thy scabbard' [Mt 26:52]. Both, therefore, are in the power of the Church, that is to say, the spiritual and the material sword, but the former is to be administered _for_ the Church but the latter by the Church; the former in the hands of the priest; the latter by the hands of kings and soldiers, but at the will and sufferance of the priest.
However, one sword ought to be subordinated to the other and temporal authority, subjected to spiritual power. For since the Apostle said: 'There is no power except from God and the things that are, are ordained of God' [Rom 13:1-2], but they would not be ordained if one sword were not subordinated to the other and if the inferior one, as it were, were not led upwards by the other. (Boniface VIII, Unam Sanctam)
Secondly, as I have already shown, the doctrine was reaffirmed by the Second Vatican Council. Thirdly, it is in the new Catechism of the Catholic Church:
2105 The duty of offering God genuine worship concerns man both individually and socially. This is "the traditional Catholic teaching on the moral duty of individuals and societies toward the true religion and the one Church of Christ."30 By constantly evangelizing men, the Church works toward enabling them "to infuse the Christian spirit into the mentality and mores, laws and structures of the communities in which [they] live."31 The social duty of Christians is to respect and awaken in each man the love of the true and the good. It requires them to make known the worship of the one true religion which subsists in the Catholic and apostolic Church.32 Christians are called to be the light of the world. Thus, the Church shows forth the kingship of Christ over all creation and in particular over human societies.33
2109 The right to religious liberty can of itself be neither unlimited nor limited only by a "public order" conceived in a positivist or naturalist manner.39 The "due limits" which are inherent in it must be determined for each social situation by political prudence, according to the requirements of the common good, and ratified by the civil authority in accordance with "legal principles which are in conformity with the objective moral order."40
30 DH 1 § 3.
31 AA 13 § 1.
32 Cf. DH 1.
33 Cf. AA 13; Leo XIII, Immortale Dei 3,17; Pius XI, Quas primas 8,20.
34 DH 2 § 1.
39 Cf. Pius VI, Quod aliquantum (1791) 10; Pius IX, Quanta cura 3.
40 DH 7 § 3.
The Catechism cites Immortale Dei and Quas Primas, showing that these teachings are not out of date. It also cites Quod aliquantum, the condemnation by Pius VI of the Declaration of the Rights of Man. And of course, Quanta Cura will stand untouched and irreformable forever because it is an ex cathedra decision.