which action on the part of the progressive has the least immediate effect on South Carolina.

It's difficult to determine a specific action taken by the progressive movement that had the least immediate effect on South Carolina as the movement had various objectives and initiatives that affected different states in different ways. However, one potential example could be their push for women's suffrage through the 19th Amendment, which granted women the right to vote in 1920. South Carolina was already restrictive in granting voting rights to minority groups, and the state did not ratify the amendment until 1969, nearly 50 years after it was passed. Therefore, in terms of immediate effect, the passing of the 19th Amendment may have had little impact on South Carolina due to the state's historical resistance to minority voting rights.