What is a presidential pardon, and how have Biden, Trump and other leaders used the power?

President Biden on Sunday issued a sweeping pardon of his son Hunter, who was convicted earlier this year on federal gun and drug charges, and pleaded guilty to tax charges in California. 

The presidential pardoning process is one that has long courted controversy, especially since many presidents issue pardons when they are leaving the White House. 

One of the most famous —and controversial— pardons in history happened less than one month into President Gerald Ford's term. On Sept. 8, 1974, Ford announced from the Oval Office that he would "grant a full, free and absolute pardon unto Richard Nixon for all offenses against the United States which he, Richard Nixon, has committed or may have committed." Ford's own press secretary resigned over the pardon, and Ford's approval rating dropped 20 points over the following days. His approval rating never recovered and he went on to lose the 1976 presidential election.