John Frame (one of my most significant modern theological influences) wrote a chapter titled “Machen’s Warrior Children,” in Sung Wook Chung, ed., Alister E. McGrath and Evangelical Theology ( Grand Rapids : Baker, 2003). Here’s the upshot:
Machen’s children were theological battlers, and, when the battle against liberalism in the PCUSA [Presbyterian Church USA] appeared to be over, they found other theological battles to fight. Up to the present time, these and other battles have continued within the movement, and, in my judgment, that is the story of conservative evangelical Reformed theology in twentieth-century America.
Read this chapter about the ongoing theological warfare in Reformed circles in what Frame considers 21 areas of ongoing debate here.