During Sally Yates's 2015 confirmation hearing for deputy attorney general, Sen. Jeff Sessions (R-Ala.) questioned whether Yates was prepared to "say no" to the president if necessary. Yates was fired by President Trump Jan. 30, after refusing to enforce his controversial travel ban executive order. (Monica Akhtar,Deirdra O'Regan/The Washington Post)

Acting Attorney General Sally Yates was fired by President Trump late Monday, after refusing to enforce his controversial travel ban executive order. In doing so, she was doing something attorneys general do in rare occasions — refusing the orders of their bosses because they believe them to violate the law.

And in fact, Yates made clear when she was being confirmed in 2015 that that's exactly what she would do, as the video above shows.

What's perhaps most interesting about the video, though, is the senator pressing her on it — none other than Sen. Jeff Sessions (R-Ala.), who is currently awaiting confirmation to the job she has been relieved of (in an acting capacity), attorney general.

SESSIONS: You have to watch out, because people will be asking you do to things you just need to say no about. Do you think the attorney general has the responsibility to say no to the president if he asks for something that's improper?

A lot of people have defended the [Loretta] Lynch nomination, for example, by saying: 'Well, he appoints somebody who's going to execute his views. What's wrong with that?' But if the views the president wants to execute are unlawful, should the attorney general or the deputy attorney general say no?”

YATES: Senator, I believe that the attorney general or the deputy attorney general has an obligation to follow the law and the Constitution, and to give their independent legal advice to the president.

SESSIONS: Well, that's true. And like any CEO, with a law firm — sometimes the lawyers have to tell the CEO: 'Mr. CEO, you can't do that. Don't do that. We'll get us sued. It's going to be in violation of the law. You'll regret it, please.' No matter how headstrong they might be. Do you feel like that's the duty on [sic] the attorney general's office?

YATES: I do believe that that's the duty of the attorney general's office, to fairly and impartially evaluate the law and to provide the president and the administration with impartial legal advice.

Sessions, of course, was asking the question in an entirely different context; when President Obama was in charge, Republicans were concerned about Obama's executive overreach, and Yates's principled opposition might be called upon to halt his agenda. Sessions followed the exchange here by asking Yates specifically about immigration -- the issue on which Obama issued far-reaching executive orders exempting millions from deportation.

But in the end, through a series of twists, she used the very same principle to halt Trump's agenda.

More from The Fix:

 Donald Trump firing Sally Yates isn’t the big story. How he did it is.

President Trump has turned ‘a pen and a phone’ into a pen and a megaphone. Thanks, Obama?

Here’s where Republicans stand on Trump’s controversial travel ban