Though President Donald Trump has slammed the network in the past, Fox News continues to play a crucial role in preserving his support.

Feted by far-right primetime hosts like Laura Ingraham, Sean Hannity, and Tucker Carlson, the network frequently allows the President's closest allies—and often the President himself—a chance to spin Trump's latest snafu in the administration's favor. Their claims often go unchallenged.

The Daily Beast reports that the Fox News research unit, known as the Brainroom, cautioned colleagues in a 192 page document entitled Ukraine, Disinformation, & the Trump Administration that the President's personal lawyer, Rudy Giuliani, had a "high susceptibility to disinformation."

The document goes on to warn against Giuliani's work to do Trump's bidding in Ukraine:

"Reading the timeline in its entirety—not a small task—makes clear the extensive role played by Rudy Giuliani and his associates, Lev Parnas and Igor Fruman, in spreading disinformation."

It also cautions against former columnist for The Hill, John Solomon, whose op-ed pieces fanned the flames of conspiracy theories that Ukraine meddled in the 2016 U.S. election—conspiracy theories Trump urged the Ukrainian President to investigate in order to obtain congressionally approved military aid from the U.S.

In addition to Giuliani and Solomon, the document also warns against conspiracy theorist Joseph diGenova and Giuliani associate Victoria Toensing, who are also implicated in a trove of documents released by former Giuliani associate Lev Parnas last month.

People wondered why Fox didn't seem to heed the warnings from its own research department.

Then again, maybe "wondered" is the wrong word.

Mitch Kweit, the Senior Vice President of Fox's Brainroom, said in a statement:

"The research division of FOX News produces a briefing book for all major stories, which serves as a standing collection of extensive data on major topics for internal use by all those in editorial functions. The Ukraine briefing book is nothing more than a comprehensive chronological account of what every person involved in the Ukraine controversy was doing at any identifiable point in time, including tracking media appearances of major players who appeared on FOX News and in many other outlets. The 200 page document has thousands of data points and the vast majority have no relation to FOX News—instead it's now being taken out of context and politicized to damage the network."

You can read more about disinformation in Active Measures: The Secret History of Disinformation and Political Warfare, available here.