Just as you'd expect from such a learned, Southern gentleman, Robert Penn Warren is skilled in a kind of courtesy and grace, while also suggesting some of the ferocity that lurks just below the surface. The man is known for his inverted phrasing, suspended verbs, and full-stop punctuation.
Ages to our construction went, Dim architecture, hour by hour: And violence, forgot now, lent The present stillness all its power. (13-16)
The effect is a kind of pent-up, held-back feeling, itself a power, as he says himself. His knowledge of meter and rhyme keeps chaos leashed; his spirit and heart strain against the boundaries, though sometimes breaking the rules. Some of his lines rhyme; some don't.
This is not a poet who rants, or even raises his voice. He makes his point by either tightening or loosening his restraint. When he does speak of some of the darker forces at work, he does so with a kind of civilized acknowledgement of those things greater than himself, that may threaten to overwhelm a person. For Warren, poetry is a way of ordering those forces.