Trump says autopen use makes Biden's pardons for Jan. 6 panel "VOID"

• It's the latest example of Trump testing the limits of executive power, and could set the stage for a legal showdown with some of his staunchest political enemies.

Driving the news: Trump contended in a late-night Truth Social post that Biden's pardons are "hereby declared VOID, VACANT, AND OF NO FURTHER FORCE OR EFFECT" and that the "necessary Pardoning Documents were not explained to, or approved by, Biden."

• The committee members should "fully understand that they are subject to investigation at the highest level," Trump wrote.
• He claimed without evidence that the members of the committee, which include former Rep. Liz Cheney (R-Wyo.), were "probably responsible for the Documents that were signed on their behalf" without Biden's knowledge.

Zoom in: As long as a pardon is valid, it is final, says Jeffrey Crouch, an American University professor and expert in federal executive clemency.

• "Other presidents have used an autopen to grant pardons," he said.

Kimberly Wehle, a University of Baltimore law professor who has written extensively about the pardon power, said Trump would likely lose a legal challenge on his argument.

• "There's no magic in the mechanism of a pardon," she said of the signature machine versus Hancock-by-hand debate.
• But that's perhaps beside the point, Wehle said. Targeting people who were already pardoned could tee up an expensive, stressful legal battle — and even if the courts were to rule against Trump, "the damage, to some degree, will already have been done."

Catch up quick: Biden, in the final days of his presidency, issued historic preemptive pardons, granting broad immunity to people whom Trump had targeted with threats to investigate or jail.

• Biden in a statement at the time said the pardons should not be construed as an "acknowledgment that any individual engaged in any wrongdoing."
• Beyond lawmakers on the Jan. 6 panel, Biden issued pardons for retired U.S. Army Gen. Mark Milley, former NIAID Director Anthony Fauci and his family members — shielding them from what he described as attacks driven "solely by a desire to hurt me."

What they're saying: "I am not afraid of Trump's latest midnight rant that has no basis in reality," said Rep. Bennie Thompson (D-Miss.), who chaired the committee, in a statement provided to Axios.

• "Donald Trump was responsible for the deadly January 6th attack on the U.S. Capitol. That is why he raced to pardon those who beat the police who protected American democracy that day as one of his first official acts after returning to the White House."

Flashback: Autopen signatures have faced scrutiny in the past.

• A 2005 memorandum opinion from the Bush Justice Department's Office of Legal Counsel said that the president may sign a bill by directing a subordinate to "affix the President's signature to it."
• "We emphasize that we are not suggesting that the President may delegate the decision to approve and sign a bill, only that, having made this decision, he may direct a subordinate to affix the President's signature to the bill," the opinion stated.

Between the lines: It's "conceivable" that the Supreme Court could treat Biden's preemptive pardons differently than traditional clemency, Wehle said.

• But it's still "unlikely," given that the high court's past precedent solidified the president's pardon power as essentially unlimited.

Go deeper: "F--k it: Release 'em all": Why Trump embraced broad Jan. 6 pardons

Editor's note: This story was updated with additional reporting.