Yates is supposed to remain the acting attorney general until Sen. Jeff Sessions (R-Ala.) is confirmed. The question now is whether she will remain in office that long.
UPDATE: Perhaps coincidentally, the Honorable William Pryor, one of the federal judges reportedly under consideration for President Trump’s initial Supreme Court nomination delivered a lecture in 2014 discussing when it is (and is not) appropriate for an executive branch official to refuse to enforce and defend a duly enacted law. His lecture was published in the Case Western Reserve Law Review here.
SECOND UPDATE: Some have asked what I think AAG Yates should have done, given her views of the EO. My answer is simple: Resign, and then publicly explain her reasons for doing so. If Yates believes that the President’s various comments about a “Muslim ban” undermine her ability to defend (or oversee the defense of) an executive action that OLC concluded (and she does not dispute) is “lawful on its face,” she should have stepped down as Acting Attorney General.
There is some precedent for this sort of thing. Recall the “Saturday Night Massacre,” when Attorney General Eliot Richardson and Deputy Attorney General William Ruckleshaus resigned rather than fire special prosecutor Archibald Cox at President Nixon’s insistence. If AAG Yates believes she is being asked to do something that violates her conscience — as she apparently does — this is the model she should have followed.
ADDITIONAL UPDATE: Monday evening, President Trump fired Acting Attorney General Sally Yates and appointed Dana Boente, U.S. Attorney for the Eastern District of Virginia, in her place.
YET ANOTHER UPDATE: I also recommend Jack Goldsmith’s parsing of Yates’ statement here.