Which group in Congress was characterized by its push for harsher measures against the South after the Civil War?

The group characterized by its push for harsher measures against the South after the Civil War was the Radical Republicans. This faction sought to impose stricter policies, including civil rights protections for formerly enslaved people and greater federal control over Southern states to ensure compliance with the new laws and amendments aimed at securing these rights. Radical Republicans believed that a more punitive approach was necessary to rebuild the South and to transform its society, which was largely characterized by its previous support for slavery. They were instrumental in the passage of the Reconstruction Acts, which divided the South into military districts and required states to draft new constitutions guaranteeing black male suffrage as a condition for reentry into the Union. Their efforts were a direct counter to the leniency often advocated by other groups, reflecting a fundamental disagreement about the nature of Reconstruction and the appropriate approach to reintegrating the Southern states into the Union.