On Monday, the White House did not rule out the possibility of Sessions invoking executive privilege at some point during his testimony.
"It depends on the scope of the questions," White House press secretary Sean Spicer said, but wouldn't elaborate. "To get into a hypothetical at this point would be premature."
But is that legal? Technically yes, according to a handful of legal experts.
Diane Marie Amann, a law professor at University of Georgia, agreed with Spicer that invoking privilege was possible: "It depends on the questions that are asked," she said.
This will be the first time Sessions has testified in Congress since he recused himself from the Justice Department's probe into Russian meddling in last year's election, and since the firing of FBI Director James Comey. Questions have arisen about Sessions' role in Comey's firing, his own involvement in the Trump campaign and his meetings with Sergey Kislyak, the Russian ambassador to the US.
"There's no doubt that conversations that involve national security in a real sense are potentially protected by an executive privilege," Amann said. "But some of the areas that have been under discussion, with regard to confidential communications, are not classified -- and don't implicate national security. That's much more of a gray area."
If Sessions chooses to opt out of answering certain questions, legal experts say the committee can hold him in contempt -- but that could elongate the testimony and could potentially take months.
"If they choose to do so, that could lead to litigation in court about whether the privilege exists and whether its applies in the instance that he invoked it," Amann said.
The committee can also work with the Trump administration to come up with a solution.
"The Committee can negotiate with the Administration to get answers to narrower or different questions or to get answers in a closed session," Lisa Kern Griffin, a professor at Duke University School of Law, told CNN. "If they do not come to any agreement, of course the matter could be litigated. The Supreme Court case that describes the scope of executive privilege arose from a similar dispute concerning the Nixon tapes."
Discussions with the attorney general on topics within the scope of the President's constitutional duties ordinarily would be protected, lawyers say.
What Sessions will and won't choose to answer "is up to him," CNN's senior legal analyst Jeffrey Toobin told Wolf Blitzer on "The Situation Room" on Monday.
"If Jeff Sessions refuses to answer questions tomorrow, he's going to refuse to answer questions tomorrow," Toobin said. "It's really under Sessions' control tomorrow which questions he wants to answer."
Still, for Sessions, there's a great deal at stake politically with this testimony. Reports last week suggested Sessions offered his resignation
to Trump because the President blamed Sessions for exacerbating his Russia problems by recusing himself from the probe.
"The peril to Sessions is a great deal more regarding those conversations with the Russians because he made sworn statements on his security clearances that appear to be contradictory to his actual record with contact with Russians," Toobin said. "That relates to his personal liability. That's what I think he's going to be considerably worried about. He's going to have some explanation, we'll see if people find it credible."