Donald Trump has sent CNN an extraordinary four-page letter that pledges legal action.

The missive from Trump attorney Charles Harder references recent videos from Project Veritas purporting to have a CNN "whistle-blower" discussing direction from the cable news network's president Jeff Zucker.

"Your own employees appear to state that CNN is focused on trying to 'take down President Trump,' driven by a 'personal vendetta' that Mr. Zucker purportedly has against him, rather than reporting the news in an objective manner," writes Harder. "In the Footage, your employees appear to state that CNN attempts to make its reporting appear neutral and unbiased, when in fact its reporting is far from neutral and highly biased against the President."

The letter contrasts aspirational ethical standards promulgated by media groups with supposed evidence that Trump says he has accumulated about CNN's bias.

"The aforementioned examples are merely the tip of the iceberg of the evidence my clients have accumulated over recent years," continues Harder. "We also expect substantial additional information about CNN’s wrongful practices to become known in the coming days and weeks. Never in the history of this country has a President been the subject of such a sustained barrage of unfair, unfounded, unethical and unlawful attacks by so-called 'mainstream' news, as the current situation."

Harder claims that CNN — now a subsidiary of AT&T— is violating the Lanham Act for making misrepresentations to the public and advertisers.

The letter adds, "Accordingly, my clients intend to file legal action against you, to seek compensatory damages, treble damages, punitive damages, injunctive relief, reimbursement of legal costs, and all other available legal and equitable remedies, to the maximum extent permitted by law."

The Lanham Act does have a provision against false advertising, though it's dubious whether Trump can demonstrate the type of commercial injury that would confer him with standing to pursue such a case over what may also be argued to be opinions (e.g. what constitutes bias). In any event, a suit would likely bring a fulsome First Amendment defense. Given how courts have treated speech and the media throughout American history, Trump's odds would seem enormously long, and while Trump was known for being litigious during his business days, he's also become infamous for being a paper tiger, repeatedly threatening litigation against media outlets without following up.

Harder is inviting a negotiation, but writes that a resolution would have to include a "substantial payment of damages."

CNN responds, "This is nothing more than a desperate PR stunt and doesn't merit a response."