Kevin Warsh has intermittently pursued the position of Chair of the Federal Reserve ever since US President Donald Trump first considered nominating him nearly a decade ago. Now, as he moves closer to taking the role, the scale of the challenge ahead is coming into sharper focus.

To be effective, Warsh must earn the confidence of at least three key constituencies: fellow Federal Reserve officials, whose votes he needs to change interest rates; financial markets, which could undermine his efforts to lower borrowing costs if they perceive him as acting on political motives; and, no less important, President Trump himselfa former real estate developer who understands precisely how interest rate moves affect heavily indebted borrowers, whether corporations, households, or even the government.

He has to walk this tightrope, said Raghuram Rajan, a professor of economics at the University of Chicago and former governor of the Reserve Bank of India. If he appears too accommodating to the administration, he will lose the support of Fed members and become unable to build consensus.

At the same time, Rajan added, alienating the White House carries its own risks, potentially placing the Federal Reserve back in the presidents crosshairs. Under Trump, current Fed Chair Jerome Powell has faced repeated criticism for not cutting interest rates as quickly as the president wanted and is now subject to a criminal investigation by the Justice Department. Powell has described the probe as a pretext aimed at pressuring him to lower rates.

Warsh may also face a difficult confirmation process in the Senate. Two Republican senators have already said they will oppose his nomination unless the criminal investigation is resolved. One of them, Senator Thom Tillis of North Carolina, sits on the Senate Banking Committee and could block the nomination from advancing if he votes against it alongside Democrats. Tillis reiterated on Friday that he would continue to oppose Warshs nomination until the Justice Departments investigation concludes.

Democratic Senator Mark Warner of Virginia, also a member of the committee, said: It is hard to trust that any Federal Reserve chair chosen by this president would be able to act with the independence the role requires, under an administration that threatens charges against any leader who sets interest rates based on economic facts and needs rather than Trumps personal preferences.

Further drama may lie ahead. Under the Federal Reserves complex structure, Powell could remain a member of the Board of Governors and the rate-setting committee even after his term as chair ends in May. That could leave Warsh facing an unprecedented situation not seen in 80 years: a former chair potentially acting as a counterweight to the new leader.

Demonstrating independence from the White House is likely to be Warshs greatest challenge. Alan Blinder, a former Fed vice chair and Princeton economics professor, said the biggest unknown is what assurances Trump may have extracted from Warsh in exchange for nominating him to lead the central bank. We know Donald Trumphe wants some kind of loyalty pledge, Blinder said. I hope Kevin Warsh didnt give him one.

Blinder noted that Warsh brings market experience and monetary policy expertiseimportant qualifications for the role. But he stressed that equally critical are Warshs interpersonal skills and his ability to influence other Fed officials during policy deliberations. What he has in abundance is interpersonal and diplomatic skill, Blinder said. He knows how to deal with people, hes very good at it, and hes widely liked.

Don Kohn, a former Federal Reserve governor who served alongside Warsh, described him as extremely smartboth intellectually and in his ability to read the room. Kohn added: He understands how important it is for the Federal Reserves decisions to be guided by a long-term view of its goalsprice stability and maximum employmentrather than the short-term objectives of whoever happens to be in the White House.