The Supreme Court on Friday made it harder to charge Capitol riot defendants with obstruction, a charge that also has been brought against former President Donald Trump.

The justices ruled 6-3 that the charge of obstructing an official proceeding, enacted in 2002 in response to the financial scandal that brought down Enron Corp., must include proof that defendants tried to tamper with or destroy documents. Only some of the people who violently attacked the Capitol on Jan. 6, 2021, fall into that category.

The decision could be used as fodder for claims by Trump and his Republican allies that the Justice Department has treated the Capitol riot defendants unfairly.

It’s unclear how the court’s decision will affect the case against Trump in Washington, although special counsel Jack Smith has said the charges faced by the former president would not be affected.