A review of Gettysburg Rebels: Five Native Sons Who Came Home To Fight As Confederate Soldiers, by Tom McMillan, Regnery, 2017.
In 1912, the renowned publisher of books on The War for Sothern Independence, Neale Publishing Company of New York, released Fighting by Southern Federals, written by Charles C. Anderson. He argued that more than 600,000 Southerners fought for the Union—men from every seceded state and the border states. He named many Union officers, including generals, ship captains, and field officers who were southern men in blue. Books and articles on Southerners’ resistance to the Confederacy have always been a cottage industry, one of the more recent being A South Divided, Portraits of Dissent in the Confederacy by David C. Downing (2017). He puts the total number of Southerner men fighting for the Union at about 300,000, and suggests that they provided the tipping point in crucial battles, including incomplete Confederate victories, for ultimate Union victory. Southern unionists represented absent brigades and divisions that General Lee or Bragg or Johnston could have used to decisive effect.
More @ The Abbeville Institute