The president signs official documents using an autograph pen, a device used to automatically sign signatures. And there are few limits on the president’s pardon power. Even if current President Donald Trump posted on social media overnight that he wanted to declare the pardons granted by Joe Biden to members of the House Special Committee investigating the 2021 attack on the U.S. Capitol to be invalid because these pardon documents were signed with an automatic signature pen, the above two points still hold true.
On March 17, US President Trump issued an article questioning Biden’s automatic signature pen.
White House press secretary Carolyn Leavitt further emphasized Trump's statement on Monday:
"Did the president even know about these pardon decisions at the time? Was his legal signature used without his knowledge?" she asked reporters.
Neither Trump nor Leavitt provided any evidence that Biden was somehow unaware of these actions, that an automated pen was indeed used on the pardon document, or that the use of an automated pen was legally controversial.
In 2005, during the second term of the George W. Bush administration, the U.S. Department of Justice studied the legality of the president's use of automatic signature pens and endorsed it.
The Justice Department said the president does not have to personally sign a bill for it to be legally binding, and that this "established legal understanding" dates back to the founding of the United States. The opinion from the Justice Department's Office of Legal Counsel said that as long as the president personally makes the decision to approve and sign a bill, he is properly exercising his authority.
John Yoo, a conservative law professor who served as a lawyer in the Department of Justice's Office of Legal Counsel during the Bush administration, said on Monday that Trump was "just having fun with Biden." You added that the conclusions reached by the Justice Department during the Bush administration were comprehensive. "I don't think the courts are going to deny that - it's based on centuries of practice and a long legal tradition of allowing agents to sign on behalf of their principals."
Biden and former President Barack Obama also sometimes used automatic signature pens to sign bills, but the issue has never been tested in court.