Although I understand theologians reacting negatively to the political abuses of Christianity in the past, I am puzzled by the vehemence of the common evangelical claim that Christianity has nothing to do with statecraft, since God’s kingdom is “not of this world” (John 18:36). The context of this saying is Pilate’s interrogation of Jesus with respect to the charges brought against him. Jesus is emphasizing that he is not the kind of king Pilate is expecting; that he is not a king of a nation within the world; that his power is not derived from the world—recognizing that kosmos in John frequently refers to the fallen kingdom of Adam established in Genesis 1:26–28 (cf. John 3:16).
But what Jesus cannot be saying is that his kingdom either does not exist on earth, or that it has nothing to do with rulership of the earth. Neither of these would make any sense whatsoever. The telos of the gospel is to fully establish God’s kingdom on earth to the exclusion of all others (cf. Matthew 6:10); and a kingdom by definition has not only a ruler, but a hierarchy of rule. The reason God’s kingdom is not of this world is not because it has nothing to do with the earth at all. It is because it does not derive its power from the existing fallen human dominion, instead imposing divine dominion onto the world through a perfect human ruler—Jesus. Indeed, God’s kingdom ultimately replaces the world, the fallen human dominion, by transforming it (Revelation 11:15)—and this is inherently earth-bound.
But if the aim is for the gospel to transform the world so that Christians ultimately rule it with Jesus (cf. 2 Timothy 2:12 etc), then divorcing this from statecraft is incoherent. The telos of the gospel is inherently political in this respect, and a primary demand of the gospel is to bring us to competence for rulership in the eschaton. Regardless of how you think that cashes out in terms of millennialism, you can’t simply divorce this key element of the gospel from the art of government, since it ultimately is the art of government.
Certainly, how you connect the gospel to statecraft will differ depending on your millennial view: for instance, if you’re premillennial you may think statecraft is only directly relevant to Christians in the millennium; whereas if you’re a- or post-millennial you’ll probably think we should be making an effort to get it right in the here-and-now. My purpose is not to stake out my view on how Christians should navigate politics, either individually or as assemblies; it is simply to point out that we must navigate politics, because a key element of the gospel is rulership of the world, and rulership of the world just is political.