Attorney General Jeff Sessions’s appearance Tuesday before the Senate Intelligence Committee will be a high-stakes test for a Trump official who has kept a low profile even as he has become a central figure in the scandal engulfing the White House over Russia and the firing of James B. Comey as FBI director.

Sessions, a former Republican senator from Alabama, will face tough questions from his former colleagues on a number of fronts that he has never had to publicly address in detail.

Democrats plan to ask about his contacts during the 2016 campaign with the Russian ambassador to the United States, Sergey Kislyak, which the attorney general failed to disclose fully during his confirmation hearing.

They also want him to explain his role in the firing of Comey, despite the attorney general’s recusal in March from the Russia investigation after revelations about his meetings with Kislyak.

“If, as the president said, I was fired because of the Russia investigation, why was the attorney general involved in that chain?” Comey said in testimony before the Senate Intelligence Committee last week.

Sessions also is likely to face questions about Comey’s cryptic assertion that the FBI knew of a “problematic” reason that Sessions should not oversee the investigation into Russian interference in the 2016 election.

Democratic lawmakers are skeptical that Sessions will divulge any explosive new details, especially since the attorney general could assert executive privilege regarding any questions about conversations with President Trump.

But they hope the hearing offers a chance to at least get Sessions on the record as either answering or dodging questions about pivotal events related to Comey and the FBI’s investigation.

“There are many unanswered and troubling questions, so the attorney general needs to be forthcoming,” said Senate Minority Leader Charles E. Schumer (D-N.Y.). “The Senate and the American people deserve to know exactly what involvement with the Russian investigation he had before his recusal, what safeguards are in place to prevent his meddling, and why he felt it was appropriate to recommend the firing of Director Comey when he was leading that investigation.”

For the embattled attorney general, the hearing will mark the first time he is questioned by senators since January, when he testified during his confirmation hearing that he did not communicate with Russian officials during the presidential campaign, when he acted as an adviser to Trump.

As the White…