We've seen quite a few in the past few days.
In short, it is one of the internal checks on power intended to limit the ability of one interest to control all aspects of governmental power.
It can be found in the plain language of the U.S. Constitution, Article 2, Section 2, Clause 1:
1. The President shall be Commander-in-Chief of the Army and Navy of the United States, and of the militia of the several States, when called into the actual service of the United States; he may require the opinion, in writing, of the principal officer in each of the executive departments, upon any subject relating to the duties of their respective offices, and he shall have power to grant reprieves and pardons for offenses against the United States, except in cases of impeachment.
For more:
- U.S. Constitution Annotated: Overview of Pardon Power.
- List of people pardoned or granted clemency by the president of the United States.
- U.S. Department of Justice - Office of the Pardon Attorney.
- Pardons Granted by President Joseph Biden (2021-Present).
- Pardons Granted by President Trump (still looking for the best link)
For a more expansive look at the powers of the U.S. President:
- Powers of the president of the United States.
