Lincoln rejected that states had a right to secede and when the Confederate States of America asked him to remove his troops from Confederate territory he refused thereby starting his war of conquest over a sovereign nation
He was not as much of a flaming liberal as U.S. Grant or Thaddeus Stevens but he was a liberal. He believed that an overintrusive central government had the right to contravene the will of the individual states. He was the president who began the march towards the overbearing central government.
Lincoln was a liberal. That’s just the way it is. Lincoln is why we have such an overintrusive government today. His presidency started the rationale for it.
All true, there is a historian named DiLorenzo (spelling?) who has documented what you say, but DiLorenzo is not accepted by the establishment historians. Neither is Arthur Herman, who wrote the revised history of Joe McCarthy, based on Soviet archival materials.
Are you going to argue that FDR was the "conservative" candidate in 1940?