President Trump’s private lawyer Marc Kasowitz has advised White House staffers—who are not his clients—not to retain their own lawyers, according to the New York Times. Kasowitz has also reportedly broken the long-standing protocol that presidents’ private attorneys operate through the White House Counsel’s office and don’t engage directly with other government employees whom they do not represent. These guidelines exist to make sure the staffers understand their rights and do not feel pressured to cooperate with their bosses’ private counsel. Kasowitz’s spokesperson told the Times these claims are “inaccurate” but refused to comment further.

As former White House attorneys have explained to TPM, Kasowitz is tasked with defending Trump personally, a job that inevitably conflicts with what is best for the White House as an institution.

But if Kasowitz did indeed tell White House staff not to retain their own lawyers, that presents additional problems. Those staffers may be interviewed in the coming months by special counsel Robert Mueller, who is investigating Russian interference in the 2016 election, possible collusion with the Trump campaign, and any administration attempts to quash the federal inquiries.

Former White House counsel Robert Bauer warned that Kasowitz’s conversations “could be interpreted as an act of obstruction, a means of dissuading the witnesses from cooperating in the investigation.”

Telling the staffers not to retain their own counsel is also to Kasowitz’s advantage, making it easier for him to interview them as he builds his defense for Trump without having to go through a pack of lawyers each time.