It’s certainly not personal loyalty. Trump doesn’t seem to have any friends in the traditional sense, and while he’s known Giuliani for years, they weren’t especially close until recently. Anyway, the president has turned on nearly every aide he’s ever had. Only a choice few have survived, and two of them are his daughter and son-in-law (though in the past he’s been happy to screw over family members, from his then-wife to his infant nephew).

Though he seldom offers it in return, Trump demands loyalty from aides, and if he senses that it is faltering, his vengeance can be swift. But loyalty alone is insufficient. Consider Michael Cohen, once one of the more sycophantic of the many yes-men in Trump’s orbit. As the FBI closed in on Cohen in spring 2018, Trump’s fixer telegraphed his devotion publicly and privately pleaded for a sign of reciprocation. But Trump (through Giuliani, as it happens) froze him out. Cohen decided to try to save himself, and Trump unleashed his ire in return.

The danger of cutting off former insiders is that they might know a lot about you—and that information can be damaging if they decide to flip. So far, Cohen has had a rougher go of it than Trump, but the continuing legal battle in New York over the president’s tax returns ultimately springs from Cohen. Maybe Trump is worried that if he were to cut Giuliani off, the former New York mayor might start spilling damaging beans.

Giuliani certainly has no qualms about giving wildly undisciplined interviews to the press, and given how troublesome some of his media appearances ostensibly on Trump’s behalf have been, what would happen if he were actually trying to hurt the president? The president already tentatively tried to separate himself from some of the Giuliani circus, disavowing any knowledge of Lev Parnas and Igor Fruman, the mysterious friends/clients/employers of Giuliani who were arrested and charged with various federal crimes in early October. Since he did so, reporters have found a long trail of connections between them and Trump. Parnas, meanwhile, fired his lawyer John Dowd—a former Trump attorney—and made known earlier this week that he’d be willing to cooperate with Congress’s inquiry.

The State Department once tried to distance itself from Giuliani, back in September. He responded by posting text messages that showed that diplomats were not only aware of his work in Ukraine but helped facilitate meetings. In the documents released yesterday, Sondland and Volker described how Giuliani insisted that the Ukrainian government make a statement citing both Burisma and the 2016 U.S. election in exchange for favorable treatment from the Trump administration, an act of extortion. These demands are the same ones that Trump made in a July 25 call with President Volodymyr Zelensky, though neither ambassador directly tied Giuliani’s intervention to Trump.