Final answer:
A presidential pardon is a constitutional power that cannot be limited by other branches of government or invalidated by other constitutional provisions or criminal statutes. Built-in safeguards such as prohibitions on ex post facto laws and bills of attainder maintain fair legal standards. State governors also have similar powers to pardon within their states.
Step-by-step explanation:
The power of pardon is a constitutional authority granted to the President of the United States and is generally considered an act that cannot be limited by other branches of government. This authority allows the President to forgive crimes and cannot be invalidated by other constitutional provisions or criminal statutes. However, there are some built-in constitutional safeguards, such as the prohibition against ex post facto laws and bills of attainder, which prevent the passage of laws or acts that would apply retroactively to criminal behavior or target individuals without a fair trial.
Historically, presidential pardons, such as President Gerald Ford's pardon of Richard Nixon and President Jimmy Carter's amnesty to draft evaders, have withstood legal scrutiny despite controversy. Similarly, state governors possess the authority to grant pardons and commute sentences within their jurisdictions. The U.S. Constitution and state constitutions both ensure that no ex post facto laws or laws implicating bills of attainder are created, protecting individuals from retroactive punishment or guilt without proper legal proceedings.