Last week, the White House revoked the press pass of CNN's chief White House correspondent, Jim Acosta, and denied him access to the building.
CNN responded by filing suit in federal court against the president.
Acosta's First and Fifth Amendment rights had been violated, said CNN. The demand: Acosta's press pass must be returned immediately and his White House press privileges restored.
"If left unchallenged," CNN warned, "the actions of the White House would create a dangerous chilling effect for any journalist who covers our elected officials." A dozen news organizations, including The New York Times and The Washington Post, are filing amicus briefs on CNN's behalf.
On Thursday, the Trump administration raised the stakes.
Justice Department lawyer James Burnham declared in court: "If the president wants to exclude all reporters from the White House grounds, he clearly has the authority to do that."