(CNN) One of the next members of President Donald Trump's administration to enter the Russia investigation spotlight finds himself in a particularly awkward spot: He's the top lawyer at the White House.

Don McGahn is expected to be interviewed in the coming weeks in special counsel Robert Mueller's investigation, along with communications director Hope Hicks and Josh Raffel, who handles press-related inquiries for White House senior adviser Jared Kushner.

The 49-year-old former Federal Election commissioner acted as a conduit of information to Trump before the President decided to fire National Security Adviser Michael Flynn and FBI Director James Comey. McGahn also served as the Trump presidential campaign's chief counsel while he was still a partner in private practice at the law firm Jones Day.

McGahn's work on both the Trump campaign and at the center of the West Wing makes him one of the few Trump team insiders who may have knowledge about several threads of the Mueller probe.

"The White House counsel would be in the position to know about the decisions that relate to the investigation," said Neil Eggleston, a former White House counsel during the Obama administration. The top White House lawyer "would be the person who interfaces with the Justice Department and the person the president would most likely talk to about those issues."

In the coming weeks, McGahn will have choices to make, including what he will share with investigators.

For now, White House special counsel Ty Cobb, who is overseeing the President's response to the Russia investigation, said McGahn isn't withholding documents from Mueller's team related to his time in the White House.

"I have no reason to believe McGahn won't fully cooperate," Cobb said.

McGahn and his private attorney for the Mueller investigation, William Burck, didn't respond to requests for comment.

"We want the special counsel to be able to say he got everything he asked for, so the American people can trust what he decides," Cobb said. Nor does Cobb see a reason to take Mueller to court over information they'd like to withhold, he said.

Confidentiality arguments

In past independent counsel investigations, lawyers in the executive branch have tried that strategy. They've attempted to resist disclosing conversations with presidents. A government lawyer's ability to stay silent could involve both executive privilege, a special confidentiality for the President's conversations with his advisers, and attorney-client privilege, which protects lawyers' conversations with their clients.

A federal court famously ordered a deputy White House counsel, Bruce Lindsey, to testify before a grand jury about potential criminal wrongdoing in Ken Starr's investigation of President Bill Clinton. Lindsey, a lawyer who normally would have attorney-client privilege, represented the office of the presidency and not the President himself, the court found. Decades earlier, the Supreme Court ordered President Richard Nixon to turn over the Watergate tapes in a ruling related to executive privilege.

"The independent counsel wanted Mr. Lindsey's testimony because he was close to the President, would have been in the critical meetings with the President and if the President had confided with or spoken with anybody, it would have been Mr. Lindsey," said Eggleston, who had argued for the White House in the Lindsey case.

The Mueller investigation already succeeded once in getting around attorney-client privilege. A court challenge about client confidentiality arose during the investigations into former Trump campaign chairman Paul Manafort and former Trump campaign official Rick Gates.

Federal prosecutors wanted Manafort's and Gates' lawyer, Melissa Laurenza, to testify about their foreign lobbying registrations. She resisted, then the chief judge of the federal court in Washington agreed that she should have to testify, because Manafort and Gates involved her in the foreign agents registration-related crime they're accused of committing. Laurenza, who worked for Manafort and Gates on filing their lobbying disclosures, is not accused of any wrongdoing. Manafort and Gates have pleaded not guilty.

McGahn still has one window where he could assert attorney-client privilege, when he served as a private lawyer to Trump's campaign.

Executive privilege

Generally, White House staff members most often defer to executive privilege when Congress presses them for certain documents and information. In practice, only the President can assert executive privilege, so it's not a staffer's choice whether to assert it. Investigators in criminal probes also have been able to overcome claims of executive privilege.

While the White House has not pressed for executive privilege, several administration officials have refused to answer questions from Congress. Some have cited the President's potential future use of executive privilege.

In October, Attorney General Jeff Sessions declined to answer several questions about his private conversations with the President before the Senate. He said at the time that the President might want to assert his executive privilege later. Senate Judiciary Chairman Chuck Grassley, an Iowa Republican, didn't force the President to use that confidentiality tool, so Sessions never had to answer.

Last week, Grassley and Sen. Dianne Feinstein, a California Democrat who's the ranking member of the Judiciary Committee, asked Kushner for more documents than he had turned over to Congress. Feinstein and Grassley said the White House claimed Kushner's lawyer sought to keep some of that information confidential under a possible use of executive privilege.

Kushner's attorney Abbe Lowell, in his response to the Senate and in conversations with CNN after, didn't directly address whether his client has deferred to executive privilege to refrain from turning over documents. "In my communication with the Senate Judiciary Committee, I said take these documents and let's talk about what else is relevant," he told CNN last week. He added that Kushner has been cooperative with committees' requests. He declined to comment further.

What McGahn would know

McGahn witnessed some of the Trump team's most crucial moments dealing with Flynn and Comey before they were fired.

Flynn is under investigation for his lobbying work related to Turkey, according to previous CNN reporting. The FBI has also scrutinized Flynn's dealings with Russia's ambassador during the presidential transition.

Neither Flynn nor Trump have been accused of wrongdoing.

McGahn spoke with former acting Attorney General Sally Yates about Flynn less than a week after the inauguration.

Yates, an Obama appointee whom Trump also fired, said she warned McGahn about Flynn's international work. She said Flynn had lied to the vice president about talks he had on Russian sanctions before Trump took office, according to her May congressional testimony.

She also told McGahn that the FBI interviewed Flynn. Mueller later inherited that FBI investigation, which now delves into Russian election meddling, potential collusion with Russians by the Trump campaign and potential obstruction of justice as it reacted to the probe. Flynn lost his White House job in February.

The Comey firing similarly put McGahn in a central role. As White House counsel, McGahn objected to a termination letter Trump wanted to send to Comey in May, according to The New York Times . McGahn marked up sections of it and suggested changes. Mueller's office has a copy of the letter, the Times reported in September. It's not clear how much of the letter addressed Trump's frustration with the Russia investigation.

McGahn also warned the President that firing Comey wouldn't stop the Russia investigation, and arranged for the President to meet with Sessions and Deputy Attorney General Rod Rosenstein to talk about Comey. Trump fired Comey the next day, using a letter from Rosenstein as the initial justification.