How do presidential pardons function as a check on the justice system?

Presidential pardons serve as a significant check on the justice system primarily by allowing the president to nullify or modify the sentences imposed by judges. This power is rooted in Article II, Section 2 of the U.S. Constitution, which grants the president the authority to grant reprieves and pardons for offenses against the United States, except in cases of impeachment. By using this power, a president can provide relief to individuals who may have been overly punished or who have demonstrated rehabilitation and deserve a second chance. This aspect of the pardoning power acts as a form of oversight over the judicial process, enabling the executive branch to correct or mitigate potential miscarriages of justice that may occur in the judicial system.