If you're going to talk about the Kingdom of God, you have to talk about other kingdoms too. This is why "politics" can never be removed from the pulpit or the concern of the church. Historically, the church has understood preaching as proclamation--heralding the "word of God" which is the true gospel of the kingdom of God. The church's identity is caught up in its' proclamation. It is dangerous to say so, but I believe that the kingdom of God is a reactionary movement, as far as we're concerned. It is reactionary insofar as it proclaims not just timeless truths about an abstract deity but specifically and prophetically speaks Christ's reign over against the reign of someone else. The gospel's affirmation of God, revealed in Christ, as true king is specifically a denial of Caesar, that typological figure, as king. The gospel's affirmation of a Kingdom of God is also an affirmation of the kingdom of God over against some other system.
Therefore, don't expect "politics" to be absent from Sundays sermons, for to proclaim with any level of meaning the kingdom of God we must name what it is that God's kingdom is not. We must name death where we see it for our God's is a kingdom over against death.
Kingdoms of the world, those that are not God's kingdom, hold no moral high ground, one over the other. "For all have sinned and fallen short..." For every kingdom, however noble it's self-understanding or language, has taken its' power (though they may call it their "freedom") and keeps its' power by the power of death. Only the kingdom which is not of this world, God's kingdom has won victory over death and keeps what we might call power, though the word "power" may hardly work if we use it the way we usually do in reference to kingdoms, by offering life to a world that knows only death and exploitation. We must proclaim this kingdom without accepting any counterfeits, which means we must talk about and name the counterfeits.