John Mitchell was a Protestant who had been a leading Irish republican in 1848. He moved to the South before the Civil War and wrote extensively in support of the Confederacy. He did not fight in the war himself. Mitchell had originally lived in NY when he immigrated, but after 1857 he lived in areas with slavery until the Confederate defeat.
He openly supported slavery, as well as the torture of slaves. He viewed slavery as a positive good and saw it as a corrective for the excesses of capitalism. Mitchell wrote "We deny that it is a crime, or a wrong, or even a peccadillo to hold slaves, to buy slaves, to keep slaves to their work by flogging or other needful correction. We wish we had a good plantation well-stocked with healthy negroes in Alabama." While he was a **** and a supporter of slavery, he claimed that the Union war aim was not to abolish slavery but to establish colonial domination of Northern capital over the Southern economy.
During the war he edited the Richmond Enquirer.