WASHINGTON — Acting Attorney General Sally Q. Yates, a holdover from the Obama administration, ordered the Justice Department on Monday not to defend President Trump’s executive order on immigration in court.
“I am responsible for ensuring that the positions we take in court remain consistent with this institution’s solemn obligation to always seek justice and stand for what is right,” Ms. Yates wrote in a letter to Justice Department lawyers. “At present, I am not convinced that the defense of the executive order is consistent with these responsibilities nor am I convinced that the executive order is lawful.”
The decision is largely symbolic — Mr. Trump’s nominee to be attorney general, Senator Jeff Sessions, is likely to be confirmed soon — but it highlights the deep divide at the Justice Department and elsewhere in the government over Mr. Trump’s order.
Mr. Trump has the authority to fire Ms. Yates, but as the top Senate-confirmed official at the Justice Department, she is the only one authorized to sign foreign surveillance warrants, an essential function at the department.
“For as long as I am the acting attorney general, the Department of Justice will not present arguments in defense of the executive order, unless and until I become convinced that it is appropriate to do so,” she wrote.
She was expected to inform the White House of her decision early Monday evening. There was no immediate response from the White House. But Mr. Trump is certain to react strongly to the open defiance to his authority.
Ms. Yates’s letter transforms the confirmation of Mr. Sessions as attorney general into a referendum on the immigration order. Action in the Senate could come as early as Tuesday.
The decision by the acting attorney general is a remarkable rebuke by a government official to a sitting president that recalls the dramatic “Saturday Night Massacre” in 1973, when President Richard M. Nixon fired his attorney general and deputy attorney general for refusing to dismiss the special prosecutor in the Watergate case.
That case prompted a constitutional crisis that ended when Robert Bork, the solicitor general, acceded to Mr. Nixon’s order and fired Archibald Cox, the special prosecutor.
Ms. Yates, a career prosecutor, is different because she is a holdover from President Barack Obama’s administration, where she served as deputy attorney general. She agreed to Mr. Trump’s request to stay on as acting attorney general until Mr. Sessions is confirmed.
Several federal judges blocked part of Mr. Trump’s executive order over the weekend after lawyers representing some of those detained at the airports quickly filed lawsuits. The judges ordered the government not to send detained people back to their home countries.
Mr. Trump’s executive order drew widespread condemnation from around the globe even as the new policy created chaos and confusion at American airports, where refugees and others who arrived on Saturday were detained for hours.
The new president characterized his order as a way to protect Americans from terrorists, and he insisted in a series of Twitter messages that his order, which named seven predominantly Muslim countries, was not an attempt to single out a religion for discrimination.
But protesters rallied at several airports around the world and Mr. Trump received a chorus of bipartisan criticism from lawmakers, academics, corporate executives and human rights advocates as travelers with valid visas or green cards were refused entry back into the United States.
Aides to the president backtracked on Sunday, saying that lawful, permanent residents of the United States would not be barred by the order. But White House officials said the president had no intention of backing down from the order, which continues to shut the borders to refugees and others.
Court motions and hearings are scheduled over the next few days in courtrooms around the country over legal challenges to the immigration order. Questions lingered throughout the day Monday about how and whether Justice Department lawyers in the field would defend the White House order.
Still, Ms. Yates’s message of legal doubt, coming from the acting head of the Justice Department, sent a powerful signal about the cloud over the order.