• Christopher A. Wray, President Trump’s nominee for F.B.I. director, will appear at 9:30 a.m. Wednesday before the Senate Judiciary Committee for his confirmation hearing.

• If confirmed, Mr. Wray will face a host of challenges, including low morale at the F.B.I., where many agents are still angry over the president’s firing in May of the F.B.I. director James B. Comey.

• Mr. Wray, a former federal prosecutor in President George W. Bush’s administration and a criminal defense lawyer, will face tough questions about whether he will maintain the bureau’s independence and resist pressure from the White House.

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What will happen during the hearing?

Expect senators to question Mr. Wray about how he intends to deal with a president who is not afraid to call the F.B.I. director, invite him to the White House for dinner and ask him to end a criminal investigation, as Mr. Comey said Mr. Trump did concerning the inquiry into Michael T. Flynn, the president’s first national security adviser. Senators will want to know that Mr. Wray is willing to resist any attempts by the president or the White House to politicize the F.B.I., which prides itself on being nonpartisan.

Democratic senators, including Dianne Feinstein of California, the ranking member on the Judiciary Committee, will also want to know whether Mr. Wray, as a high-ranking Justice Department lawyer in the years after the Sept. 11 attacks, played any role in providing legal guidance to Bush administration lawyers who signed off on the C.I.A.’s torture of terrorism suspects in the hunt for the attackers.

What about the F.B.I.’s Russia investigation?

Don’t be surprised if senators want to get Mr. Wray’s legal take on the F.B.I.’s investigation into Russian meddling in the election and the most recent development on that matter. The New York Times revealed that the president’s eldest son, Donald Trump Jr., received an email last summer from an intermediary promising damaging information about Hillary Clinton and furnished by the Russian government. That revelation has dominated the news over the past few days and could come up at the hearing.

Mr. Wray’s views on the F.B.I.’s use of surveillance tools and encryption could be examined, too. Republicans are likely to ask whether he will ensure that the F.B.I. vigorously investigates a spate of recent leaks of classified information to the news media, many of which have been embarrassing to the president and that Republicans have condemned.

Who is Mr. Wray?

Former colleagues and friends describe Mr. Wray as a low-key straight shooter who is unafraid to take on tough cases. Mr. Wray, 50, spent years as a high-powered defense lawyer. According to financial disclosures, Mr. Wray has made $9.2 million since the beginning of 2016 as a partner with the law firm King & Spalding, where he has spent almost 12 years with the firm, representing major corporations and also New Jersey’s governor, Chris Christie.

Before joining the private sector, Mr. Wray worked in the Justice Department. He started as a prosecutor in Atlanta and became associate deputy attorney general in Washington in May 2001, putting him at the center of the country’s response to the Sept. 11 attacks. As the head of the department’s criminal division from 2003 to 2005, Mr. Wray was responsible for investigating C.I.A. abuses of detainees, including the deaths of two men in Afghanistan and Iraq.

Mr. Wray graduated in 1989 from Yale University and received his law degree in 1992 from Yale Law School.