Why did Lincoln refuse to pardon confederate leaders?

Lincoln refused to pardon Confederate leaders because he believed that accountability was necessary for national healing and reconciliation after the Civil War. He felt that granting pardons too readily would undermine the sacrifices made by Union soldiers and could enable a resurgence of the rebellion. Additionally, Lincoln aimed to set a precedent for the reintegration of the South into the Union that involved a commitment to loyalty and the principles of the Constitution. His approach was part of a broader vision for a unified nation that emphasized restoration rather than retribution.