For those following or interesting in the debate about the Two Kingdom understanding of Christ and culture, you may want to check out the responses by Jason Stellman and Daryl Hart (at the new White Horse Inn blog) to the post by Kevin DeYoung.
Kevin posts a brief response today, mostly agreeing with what they say (though offering a bit of pushback on areas like abortion and adoption ministry). Kevin also recently posted some areas where he sees common ground among the 2Kers and the Neo-Kuyperians.
For those wanted to explore Luther's understanding of these issues, William J. Wright's book, Martin Luther's Understanding of God's Two Kingdoms, is being published by Baker Academic in January 2010. Going back historically is often a fruitful way of moving forward in contemporary discussions.