Update: That didn’t take long:

.@POTUS has named Dana Boente, US Attorney for the Eastern District of VA as Acting Attorney General. Sally Yates has been relieved.

— Kayleigh McEnany 45 Archived (@PressSec45) January 31, 2017

Here’s a statement from the White House saying Yates “betrayed the Department of Justice”:

.@POTUS fires acting AG Sally Yates for "refusing to enforce a legal order designed to protect the citizens" of US pic.twitter.com/9LOufrREHE

— Jake Tapper (@jaketapper) January 31, 2017

Update: Jonathan Adler at the Washington Post notes that Yates explanation for her decision has an unusual and possibly unique basis. From the Post:

Yates does not claim that she cannot defend the executive order because it is unconstitutional or because the Justice Department would be unable to offer good-faith arguments in defense of its legality. To the contrary, Yates claims she is ordering the Justice Department not to defend the executive order because it is not “wise or just.” This is quite significant. I am not aware of any instance in which the Justice Department has refused to defend a presumptively lawful executive action on this basis.

[End update]

CNN reports that acting Attorney General Sally Yates, a hold over from the Obama administration, has ordered the DOJ not to offer any defense of Trump’s executive order on immigration. From CNN:

“My responsibility is to ensure that the position of the Department of Justice is not only legally defensible, but is informed by our best view of what the law is after consideration of all the facts,” she said in a letter. “In addition, 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.”

“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,” she wrote.

Yates is serving as acting AG until Jeff Sessions, Trump’s nominee for the post, is confirmed. Sessions is scheduled to be voted on by the Senate Judiciary committee tomorrow. A vote by the full Senate will follow.

Meanwhile, the Council on American-Islamic Relations (CAIR) has filed a lawsuit challenging the constitutionality of President Trump’s executive order on immigration. From Politico:

The filing acknowledges that the executive order is in some ways more narrow than Trump’s December 2015 call for “a total and complete shutdown of Muslims entering the United States until our country’s representatives can figure out what is going on” in that it “applies only to a subset of Muslims rather than all Muslims.”

Nonetheless, the lawsuit repeatedly refers to the action the “Muslim Exclusion Order” and says it fulfills Trump’s “longstanding promise and boasted intent to enact a federal policy that overtly discriminates against Muslims and officially broadcasts a message that the federal government disfavors the religion of Islam, preferring all other religions instead.”

The lawsuit was filed on behalf of 20 Muslims who are not identified by name in the lawsuit. This is not the first lawsuit against the order. Last week the ACLU filed a lawsuit which resulted in “a nationwide temporary injunction that will block the deportation of all people stranded in U.S. airports under President Trump’s new Muslim ban.”

Here is video of the CAIR announcement of the lawsuit.