A federal judge has ruled that two defendants accused of storming the U.S. Capitol on Jan. 6 must face a felony charge of obstructing an official proceeding, the first such opinion on a charge that has become a bedrock in Capitol riot prosecutions.

U.S. District Judge Dabney Friedrich of the District of Columbia denied a motion by a lawyer for one of the defendants, Ronald Sandlin, to toss out the charge, ruling that the congressional session to certify the election results constituted an “official proceeding” and that Sandlin’s alleged conduct in preparing for violence and striking a police officer violated the obstruction statute.