Trump’s former lead lawyer John Dowd had been the only member of the president’s personal legal team with a security clearance, the people said. When Dowd quit in March over disagreements with Trump on legal strategy, Jay Sekulow became the lead lawyer on the investigation and is still waiting for his clearance.

The lack of security clearances could further complicate already sensitive talks with Mueller’s team. Prosecutors for Mueller made clear to Trump’s lawyers before Dowd left the legal team that the special counsel would consider a subpoena compelling the president to testify before a grand jury if he refuses to participate in a voluntary interview, Dowd told Bloomberg News.

Mueller believes he has legal standing to subpoena a sitting president, even though such a move has never been fully tested, according to the two current U.S. officials. Unlike an interview, Trump couldn’t bring his lawyers into a grand jury room.