Former New York City Mayor Rudy Giuliani said that if President Joe Biden issues blanket pardons, they could end up being challenged in the Supreme Court. 

"I think if he does it across the board....these blanket pardons of maybe eight to 10 people, then we'll have a real Supreme Court test of whether the blanket pardon is unconstitutional," Giuliani said on the "Just the News, No Noise" TV show.

Biden earlier this month pardoned his son on gun and tax charges, as well as any other crimes committed in the last ten years, despite promising not to make such a move.

Congressman Andy Biggs, R-Ariz., predicted that Biden would pardon his brother James. 

Giuliani said that many law professors wrote against President Gerald Ford pardoning President Richard Nixon, arguing it wasn't constitutional. 

"You cannot give a pardon for a crime that may be committed because the pardon power derives from the power of the King of England," he said. "The King of England could only pardon what he knew about."