Joe Biden’s presidential campaign made an extraordinary request to executives of top news channels on Sunday, asking them to no longer book Donald Trump’s personal lawyer, Rudy Giuliani, on their programs.

In a letter addressed to the heads of the major news and cable networks, as well as top news anchors, two top Biden campaign advisers make the case that by peddling routine falsehoods about the work of Biden and his son Hunter in Ukraine, Giuliani’s presence on the airwaves is editorially untenable.

“We are writing today with grave concern that you continue to book Rudy Giuliani on your air to spread false, debunked conspiracy theories on behalf of Donald Trump. While you often fact check his statements in real time during your discussions, that is no longer enough. By giving him your air time, you are allowing him to introduce increasingly unhinged, unfounded and desperate lies into the national conversation,” the letter from top aides Anita Dunn and Kate Bedingfield reads.

“We write to demand that in service to the facts, you no longer book Rudy Giuliani, a surrogate for Donald Trump who has demonstrated that he will knowingly and willingly lie in order to advance his own narrative,” the letter continues.

The Biden campaign letter goes on to note that “Giuliani is not a public official, and holds no public office that would entitle him to opine on the nation’s airwaves.” And it demands that if the former mayor is put on the airwaves, “an equivalent amount of time” be given “to a surrogate for the Biden campaign.”

In a text response to The Daily Beast, Giuliani said the Biden letter “sounds like the usual left wing censorship. Everything I say is supported by such as today, affidavits and statements. They are the ones who have covered up pay for play for at least 5 years.”

In a tweet, Trump 2020 campaign manager Brad Parscale quipped, “Can we request the removal of Democrats on TV that push hoaxes? Wait, but then who would do the interviews?”

Political campaigns have complained about bookings since the advent of politically-oriented television news. But rarely, if ever, has one campaign made an affirmative demand that a top aide to a rival candidate no longer be given a platform.

But Giuliani has pushed the bounds in ways few guests have before. The former New York City mayor and presidential candidate has been a repeat guest in recent days on numerous networks, during which he has peddled debunked-arguments about Hunter Biden’s work in Ukraine and Joe Biden’s efforts to remove a prosecutor in that country. During the course of those appearances, Giuliani has ignored that the prosecutor was facing pressure from much of the global community to resign and that the case against Hunter Biden—who was serving on the board of the Ukrainian gas company Burisma—was dormant during the time Joe Biden demanded that the prosecutor step down.

From there, Giuliani’s appearances have delved into the conspiratorial, so much so that Trump’s former top homeland security adviser, Tom Bossert, admonished him during his own news hit on Sunday.

According to a Biden campaign source, the letter was sent to all of the major network heads including NBC President Noah Oppenheim, CBS News President Susan Zirinsky and CNN President Jeff Zucker, along with hosts like CNN’s Jake Tapper, NBC’s Chuck Todd and Fox News’ Chris Wallace.

While some Democrats have reveled in Giuliani’s news tour, noting that he has managed to implicate several top State Department officials in his scheme to pressure Ukraine leadership to dig up dirt on Hunter Biden, the Biden campaign clearly does not share that schadenfreude.

“Your obligation is to provide the American people with an informed, fact-based and responsible coverage and debate of critical issues,” their letter reads. “Rudy Giuliani has made very clear that his only obligation is to protect Donald Trump, and that he will willingly lie to do so. While you have been aggressive in pushing back on him in real time, it is well known that the dedicated liar always has the advantage, pushing out outlandish falsehoods and disinformation in the knowledge that it is hard for the corrections to catch up.”