The senator primed to replace the acting US attorney general fired by Donald Trump for questioning whether his travel ban was lawful once grilled her at a hearing over her ability to defy a presidential order.
The recorded exchange between Senator Jeff Sessions and Sally Yates in 2015 has gained huge interest online after being seen in a new light following her dismissal and speculation that Trump will nominate him to succeed her.
Ms Yates, the Government's top lawyer, had ordered officials not to enforce the executive order banning travellers from seven Muslim-majority nations.
Mr Sessions had walked Ms Yates through the exact scenario during a confirmation hearing for her appointment as deputy attorney general.
During an exchange on dealing with the Oval Office, he asked her: "Do you think the attorney general has the responsibility to say no to the president if he asks for something improper?"
Mr Sessions then added: "If the views the president wants to execute are unlawful should the attorney general or the deputy attorney general say no?"
Ms Yates replied: "Senator, I believe 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 endorsed her answer, saying: "Well that's true."
The Republican senator from Alabama went on to test Ms Yates on her ability to stand up to intense political pressure from the office then occupied by Barack Obama.
He characterised a determined president with an analogy more familiar to the business world most familiar to Obama's successor Mr Trump.
"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. (It'll) get us sued. It's going to be in violation of the law, you'll regret it, please.' No matter how much headstrong they might be."
Mr Sessions then asked: "Do you feel like that's the duty of the attorney general's office?"
Yates replied: "I do believe that's the duty of the attorney general's office, to fairly and impartially evaluate the law and provide the president and the administration with impartial legal advice."
Announcing her dismissal on Monday, the White House said Ms Yates had "betrayed the Department of Justice by refusing to enforce a legal order designed to protect the citizens of the United States".
The potential nomination of Sessions by Trump is expected to pass in the Republican-led Senate despite opposition from Democrats.
"Many people have doubts about whether Jeff Sessions can be that person, and the full Senate and the American people should at the very least know exactly how independent he plans to be before voting on him," the Senate's top Democrat, Chuck Schumer, said in a statement after Ms Yates' dismissal.
President Trump accused the Democrat senators of deliberately stalling his appointments.