The White House turned away reporters from CNN, MS NOW and Politico on Saturday morning, putting President Donald Trump’s White House press ban into effect one day after he announced it on social media. Security officers seized press credentials as the journalists arrived for work, according to the three outlets, setting up what First Amendment experts say will likely become a courtroom fight over press freedom in America.

Trump announced the ban Friday on Truth Social, declaring it effective immediately and accusing the three news organizations of repeatedly publishing what he called fake news. He pointed to no single story or incident as the trigger, telling reporters in the Oval Office that the move reflected years of negative coverage and what he described as cumulative stories over the last few years. The president also warned that other outlets could follow, naming the New York Times and the Washington Post as examples of outlets he considered fake news, though he stopped short of banning them.

Saturday morning at the White House gates

Enforcement of the White House press ban began early Saturday. CNN reporter Betsy Klein was denied access at the White House gates, and a Secret Service agent told her the press pass had been deactivated, CNN reported. Klein said the agent offered no explanation beyond referring her to the White House press office. Politico reporter Cheyenne Haslett was also turned away later Saturday morning, and Politico global editor Jonathan Greenberger told colleagues in a memo that the company would vigorously defend its First Amendment rights.

MS NOW correspondent Akayla Gardner said an officer asked her to hand over her badge after it failed to scan at the press entrance. When Gardner asked why she could not enter, the officer said the decision was above him, according to Reuters. A photographer for the network was also denied entry, though one MS NOW producer managed to scan through successfully. Crews from the affected networks ended up reporting live from outside the White House perimeter while photographers and tourists looked on.

CNN called the ban an illegal assault on its constitutional right to report on the government without interference. MS NOW said it intends to take any and all steps necessary to defend its First Amendment rights and the role of independent journalism. Politico said it stands behind its reporters covering the White House. All three organizations signaled they are prepared to take legal action.

A legal fight over the First Amendment

First Amendment experts have described the White House press ban as unconstitutional. Bruce D. Brown, president of the Reporters Committee for Freedom of the Press, called a ban like this flatly unconstitutional on Friday, arguing that once the White House invites some journalists inside, it cannot exclude others because of their coverage. He characterized the move as textbook viewpoint discrimination and predicted courts would strike it down if challenged.

The White House Correspondents’ Association, which represents the broader press corps, said the ban violates the First Amendment and warned that a standard used to exclude one outlet over its coverage could eventually be applied to any outlet. The association called on the Trump administration to restore the affected journalists’ access immediately. The New York Times labeled the ban yet another retaliatory and unconstitutional threat and said it stands with the targeted organizations. Clayton Weimers, executive director of Reporters Without Borders North America, accused the president of trying to control who covers him, adding that press access exists so the public can be independently informed.

The move fits a pattern. Last year the White House barred the Associated Press from the press pool after the agency declined to adopt Trump’s preferred name for the Gulf of Mexico, a ban the AP challenged in court. During his first term, the administration sought to revoke or suspend the credentials of Playboy correspondent Brian Karem and CNN’s Jim Acosta, but federal judges ordered their press passes restored. USA Today reported that many of the practical details of the new ban remain unclear, including whether it means revoked badges, removal from the press pool, or exclusion from the entire White House campus.

The timing adds political weight to the story. Trump’s approval rating sits near record lows in most polls, according to USA Today, and Republicans face headwinds heading into November’s midterm elections, with Democrats widely favored to take the House. Some commentators have speculated that the ban is an attempt to shift attention from an unpopular war in Iran and rising gas prices, though the White House has not offered an official justification beyond complaints about coverage.

The standoff now lands in the middle of a busy stretch for the administration, which this week also locked in a permanent US security arrangement in Greenland after months of tension with Denmark. But the press fight may prove the more immediate problem. CNN is scheduled to serve as the television pool for Trump’s trip to New York for the United Nations general assembly on Monday, and the five major networks are in active discussions about how the pool can function with one of its members locked out. With legal challenges expected within days, the White House press ban looks set to move from the gates of 1600 Pennsylvania Avenue into a federal courtroom.