Most have seen the Michael Knowles clip (that link is to a liberal’s hysteric and false reaction to the clip) from CPAC going around. This pastor’s outraged response to it is a good opportunity to make an observation regarding Two Kingdoms theology and the political application of “the gospel.” Clip:

This is precisely the fruit of using the gospel—which has heavenly kingdom relevance—to regulate temporal-political affairs. This argument is that because the gospel treats people in X way, so the political kingdom must treat people in X way. This is the social gospel.
In the late nineteenth century, progressives took over much of American protestant institutions. They pushed their social gospel which basically leveraged evangelical rhetoric for Leftwing political objectives. Their “heaven on earth” progressive postmillennialism was a major corruption of the Protestant faith and it finally culminated in Progressive Era and Woodrow Wilson.
One response to this mistake has been to radically separate church and state. The contemporary rendition of this is embodied in the R2K circles at Escondido. One of the several things they argue is that you should not use the gospel for political ends. They are correct in this. Where they go wrong is in assuming that therefore the Christian religion should not have anything to do with matters of state, of the civil polity. In this they are wrong.
The response to R2k has come in various types of transformationalists, postmillennialists, theonomists, and so forth. They argue that the R2k vision has allowed (or would allow) the Left to take over and for our Christian institutions to eventually get pummeled by a revolutionary Left. They are correct in this. Where they go wrong is in arguing that we need to recover the gospel as a key element in our kingdom building. The Progressives wrongly employed a wrong gospel for evil ends. But the transformationalists seek to correct this.
I disagree with both R2k and transformationalism. The answer is the classical 2K doctrine: that there are indeed two kingdoms, one temporal and natural, one eternal and heavenly. The gospel is specific to the heavenly order. It does not solve socio-political problems. Rather, we rest on the creation order, the Natural Law, the particularity of political problems in light of the particular needs of particular peoples (all within the confines of a Christian-Augustinian metaphysic). The Christian religion, the Christian view of the cosmos, does speak to these things in a way that precedes and is independent from (but ultimately is restored by) the gospel itself and its narrow application.
On the Michael Knowles clip, he is correct. Transgenderism as an ideology threatens the integrity of the created institution of marriage, and the divine purpose of sex. It is a specifically public threat, not relegated to personal and private harm. Therefore, pursuing its elimination is good; not on “gospel” terms, but as a matter of public order.