Current and former prosecutors say Mr. Sessions’s tepid response reflects efforts to appease Mr. Trump, even at the expense of morale among the department’s employees, and has raised fears that prosecutors cannot depend on protection from political interference.

“Attorneys general swear an oath to protect and defend the Constitution, not the president,” said Matthew S. Axelrod, a partner at Linklaters and a former Justice Department official who began as a federal prosecutor under Mr. Bush. He left the department after his boss, Sally Q. Yates, was fired by Mr. Trump when she refused to defend his travel ban. “Institutions like the D.O.J. rely on their leaders to be a voice that defends them. It’s critically important to this institution that its leadership have its back.”…

“Sessions’s silence is evidence that Trump’s public neutering of anyone close to this investigation is working,” said Paul Pelletier, a Democratic candidate for Congress in Virginia who was a federal prosecutor for nearly three decades. “It is deleterious to the whole criminal justice process.”