Hmmm. This article gives a pretty clear picture of what it means to be kingdom people living within various other kingdoms:

Politics per se are not the church's business. The church is not to preoccupy itself with results. It has not even to practice "pacifism," that is, reject arms with the object of stopping war. No, God expects only one thing of it: that it walk in obedience to the gospel, refusing violence in whatever form because of that obedience, without concerning itself with the consequences, good or bad, that such refusal may involve. Such faith puts into practice the justice that marks God's kingdom. The church's business is not to establish peace between the nations, but to bear witness to the love of God, to live in his peace and righteousness...

One might well imagine a scene at the Last Judgment, before the throne of God. There, side by side in the dock, are the state and the church. God addresses the state first, demanding an account of its crimes: "Why did you tolerate the exploitation of the poor? Why have you oppressed, persecuted, tortured, and murdered? Why did you make war on other nations, devastating their cities and killing by the millions?" The state will bow its head, knowing it has sinned, and will ask for pardon. It will also plead an extenuating circumstance. "The church here," it will argue, "never translated your commandments into practical deeds. It never prophesied or showed the way. Instead it became rich. It became an institution where earthly concerns tempered its zeal. It collaborated with me and gave me its blessing. It was because of its blindness that I went astray. I accept your judgment, but also ask that the church be more severely condemned."

Then God will turn to the church and say, "Why did you say nothing when you saw the rich in your midst exploiting the people? Why did you pretend not to know what the state was doing, how it was oppressing, imprisoning, and torturing? Why did your members take part in its wars? It was not your part to be the soldier's foot, the hand or the brain of the nuclear technician, the arm of the artilleryman or the pilot, but the clear-sighted eye, alert and ready to give the body of the state warning of the abyss toward which it was moving."

God will not relent. "You were my chosen one, but you have renounced your vocation. You were charged with a special mission, but you cast it aside. Like Jonah, it was your fault that the storm broke loose and the ship almost foundered. If Jonah had not repented, Nineveh would not have heard his message, would not have repented, and would have been destroyed. Now you have not followed Jonah on the path of repentance, and because of you I am obliged to condemn the state..."