I’m going to take for granted a step that some of you are not inclined to grant, in order to advance this second part. That step is a number of convictions:
a) Individual Christians are called to enemy-love, not self-defence or personal vindication. (I think a good case for this can be made from the classic texts of Matthew 5:38-48 and from Romans 12:14-21, among other places and a broader Christological ethic)
b) The church as a corporate body is also called to enemy-love, not self-defence or personal vindication.
c) The ruling authorities in the world have judicial power for the execution of judgment (Romans 13)
Now, let me come to the point of my philosophical confusion. If Christians are called to a life of enemy-love, both individually and corporately, which eschews violence, how can this be overturned when Christians are considered corporately under a different aegis? That is, if you think about a collection of Christians as a church, one would deny that they had any authority for violence and judicial-force, but if you reconstituted the same collection of Christians as a civil authority, then they should pursue such violence? Of course, the objection could simply be made that in different places and roles I have different values and functions and authorities to carry out. Let me suggest though, that this contrast between ethics of Christian life and secular authority is more than simply what my governmental office might permit me to do, it goes close to the core of Christian ethics.
This is where it is helpful to consider the articulation of the Reformer’s doctrine of the two kingdoms of God. I agree, that God does indeed rule the world by means of two reigns, two kingdoms, the one of secular government, the other the spiritual kingdom nascent in the church. Such two kingdoms are united and overlaid in the nation of Israel, which is why you see the twin exercise of coercive and spiritual authority in the same body. The two kingdoms are distinctly separated in the NT, as I believe can be seen both by (a) Jesus’ relation to secular authorities (Mt 22:21 for instance), (b) the spiritualisation of church discipline and judicial function (excommunication as the sign of spiritual exclusion and thus death, not matched to any temporal death).
The key question is what sort of role may Christians legitimately pursue in the realm of secular authority, that will not compromise their allegiance to Jesus? The NT addresses a situation of political disempowerment, where rulers were far from paradigms of justice, and Christian involvement was negligible to non-existent. Nonetheless, I think it’s a far characterisation of the NT that the real work of God and focus of Christian effort is to be the spread of the Kingdom by lives of witness and work in the world. i.e., the primary focus of Christian lives is seen in the spiritual means of the Heavenly Kingdom, not the coercive means of the ruling powers. Indeed, the realpolitik of fallen and unredeemed rulers and tyrants reminds us that God rules providentially through whatever ruling authorities there happen to be, irrespective of their devotion to him. That, too, is the treatment of the OT, where the judgment of Israel by foreign nations is likewise portrayed as God’s providential ruling of the kings, without exoneration of their sins.
If we’re looking for a terminus ad quem for Christian involvement in secular government, I propose minimally that it must be the avoidance of any kind of dual-minded mentality. Contra Luther, it’s not okay for the Christian to be not-retaliatory in his personal life, but put on the cap and baton and mete out judicial violence in the community. Such a bifurcation of moral realities is unsustainable psychologically and morally for the individual, and disingenuous about the integrated reality of human moral communities. We may live in a world where God reigns by two modes, but Christians should be wary of thinking that the latter can be redemptive.