Story highlights In 2015, Sally Yates told Sen. Jeff Sessions she had to follow the law, the Constitution

Yates was fired after defying White House over defense of its immigration order

(CNN) Sally Yates had been in the crossfire over her constitutional duty before her ouster Monday night as acting attorney general.

Video of Yates' 2015 confirmation hearing as deputy attorney general shows Sen. Jeff Sessions grilling her about her responsibility to then-President Barack Obama should he require her to execute "unlawful" views. Sessions is now Donald Trump's pick to lead the Justice Department.

"You have to watch out because people will be asking you to do things and you need to say no. You think the attorney general has the responsibility to say no to the President if he asks for something that's improper?" Sessions asks Yates.

"A lot of people have defended the Lynch nomination, for example by saying, 'Well, he appoints somebody who's going to execute his views, what's wrong with that?' " the GOP senator from Alabama asks, referring to Obama's 2014 nomination of Loretta Lynch as attorney general.

"But if the views the President wants to execute are unlawful, should the attorney general or the deputy attorney general say no?"

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