UPDATED 9:31 p.m. ET: Shortly after Sally Yates ordered Justice Department lawyers not to defend Donald Trump's immigration ban, White House Press Secretary Sean Spicer announced her termination. Dana Boente, the U.S. Attorney for the Eastern District of Virginia, will serve as acting Attorney General.

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Acting Attorney General Sally Yates, a Barack Obama appointee, has told the Justice Department lawyers not to make any legal arguments in defense of Donald Trump’s immigration ban.

According to the New York Times, Yates sent out a letter to the Justice Department lawyers, stating she does not believe the executive order to be lawful.

“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,” Yates wrote. “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.”

It’s a huge blow to the president and supporters of the controversial ban, which many have criticized for discriminating against Muslims; however, it’s important to note that Yates is a holdover from the Obama administration, and that her order will only be enforced until her successor is confirmed by the Senate. Trump has nominated Jeff Sessions for the position.

As pointed out by the Times, Trump has the authority to terminate Yates before a new AG is confirmed, but “she is the only one authorized to sign foreign surveillance warrants,” which makes her essential to the department.

Shortly after Yates' order made headlines, Trump sent out a tweet in which he labeled Yates "an Obama A.G."