Here’s a paper from the Water Is Thicker than Blood blog, which I’ve discovered to have some high-quality Machen entries. An excerpt from this paper:
Machen’s seemingly peculiar viewpoint can be seen in the cultural controversy of the day, as well as in the ecclesiastical confessionalism he was singularly dedicated to throughout his life at Princeton and in the formation of Westminster Theological Seminary. As a southerner, Machen “shared his family’s aristocratic sympathies throughout his life.” His loyalties lay with Southern culture in a distinct fashion, putting him on the side of constitutional states’ rights and belief in the legitimacy of secession. This view point led him to a libertarianism where he “opposed almost any extension of state powers and took stands on a variety of issues.” George Marsden further comments on his views stating that as a libertarian he did not easily fall into the categories of ‘liberal and conservative.’ Machen’s outlook concerning liberty in society was built upon philosophical and theological convictions. “Only be preserving free speech, he said, was there hope for the one instrument that could stop radicalism. ‘That instrument is reasonable persuasion.’” These convictions were in stark contrast to the Northern sentimentalities of the church he was to become associated with through teaching at Princeton.
Read more: Secessionism and Presbyterianism.