Robert M T Hunter was one of Virginia's senators in 1861 and also probably its most prominent figure nationally. He became confederate Secretary of State after he left the senate. A former Speaker of the House, he was generally regarded as the south's go-to man in Congress on economic matters before the war. He regularly led the south's efforts on any tariff legislation, is credited with securing the votes to pass the 1857 tariff reduction, and became the south's floor leader in opposition to the Morrill Act in 1860 and 61. Hunter held great influence in Virginia politics as well. Hunter initially opposed secession and sought to facilitate compromise by acting as a middle man between Lincoln and the CSA commissioners who came to negotiate the conflict with Lincoln before the war, but when he realized negotiations were not possible with Lincoln he informed the VA legislature that secession had become their only course.
But most importantly of all to this discussion, Hunter was a free trader. He was also a free trader of greater prominence and influence in Virginia than ANY of the men mentioned in that article. Yet its authors did not see it fit to say one word about Hunter. That suggests to me that they are neglecting a key part of the equation for the reason that it contradicts their thesis of relatively strong protectionism in Virginia.