There is nothing Donald Trump enjoys more than firing fresh salvos in his battle against the mainstream media, which he likes to dismiss as “fake news”.

Now, he has lit the touchpaper in his most aggressive effort yet to demolish decades-long customs and practices over who gets to film the US President’s daily activities – and how they are permitted to report them.

On Friday, Trump unleashed his pliant Department of Justice on the five leading US broadcast news networks: ABC, CBS, NBC, CNN and Fox News. As the permanent members of the White House TV pool, they have been put on notice that they are under investigation for possible violations of federal antitrust laws.

The probe relates to the solidarity expressed last month following Trump’s efforts to ban CNN and two other media organisations from the White House grounds. The other four broadcasters temporarily downed their TV pool duty tools in response.

This meant that Xi Jinping’s lavish state visit to Washington received little in the way of trailing US television crews, forcing even Trump-friendly right-wing media to scramble to find usable footage.

CNN, MS NOW TV and have since regained access to the White House, but only thanks to a temporary restraining order issued by a judge. Meanwhile, Trump’s efforts to upend the arrangements governing coverage of his daily events have continued apace.

Trump clearly hopes the probe will permit him to publicly accuse the five networks of conspiring with one another to undermine media coverage of his administration. This could spark a fresh effort to restrict “unfriendly” journalists from the White House grounds.

In a statement on Saturday, Department of Justice spokesperson Emily Covington accused the five networks of having “proudly boycotted White House events”. She also confirmed that the antitrust investigation was underway and warned that “group boycotts among commercial competitors can violate the Sherman Act”, a law dating back to 1890 that bans monopolies and anti-competitive agreements.

The five networks have received letters requiring them to surrender communications between them in the hours after Trump announced his media ban on 18 September, when he accused CNN, MS NOW and of reporting “fiction and lies” about his administration.

It’s unlikely Trump envisaged the possible repercussions of his actions back then. By the following week, the TV pool had abandoned its efforts to cover Trump’s daily activities, leading to huge gaps in available footage related to his visit to the United Nations General Assembly on 22 September, and the Chinese state visit later that week.

When several broadcast networks used only still images of Trump’s trip to New York and the arrival of Xi, the US President complained on social media that they had “refused” to cover “the biggest and most beautiful events to take place in many years”.

He also said the networks’ refusal to cover Xi’s visit to the White House via a broadcast pool – which is then shared with other broadcasters – was due to the fact that “they’re fake news, and because they knew how good it would be”.

Trump’s frustration with how the media is covering him seems to be growing ahead of the midterm elections next month.

Last weekend, the President took to Truth Social to air his grievances against Fox News, a long-time ally, which has decided not to air in full his recent campaign rallies. He wrote that Fox News “spends more time talking to Communists, Socialists and Dumocrats, often without rebuttal, and Maga is not, to put it mildly, happy”.

It’s likely the probe into the networks’ possible breach of federal law will take time to advance. They will challenge even the requirement for them to submit documents to the investigation, arguing that their communications are covered by free-speech protections enshrined in the US Constitution.

This creates a problem for the most media-hungry President the US has ever had.

Trump craves two things simultaneously: full coverage of his own attention-grabbing activities each day, but also the power to control the language and images used to describe his increasingly unpredictable administration.

After the White House TV pool suspended its activities, top Trump communications staff made a series of urgent calls to lower-level broadcasters, in an effort to try to persuade them to join a new-look TV pool, with plans to include several outlets seen as loyal to Trump’s Maga vision. 

Some are known to have refused the administration’s proposal, but at least one, small pro-Trump outlet, Real America’s Voice TV, quickly volunteered to share video with other broadcasters. It was a far cry from the resources and expertise that the major networks have at their daily disposal.

Trump wants publicity to be on him around the clock. But he also aches to punish the major broadcasters when they paint him in an unfavourable light, and to terminate the key role they play in disseminating unvarnished coverage of daily events.

A fresh confrontation was inevitable, and Trump has now unleashed his Department of Justice Rottweilers in a seeming effort to spark one.