Lacking any substantive legislative wins, embroiled in an ever-widening F.B.I. collusion investigation, and battling historically low approval ratings, Donald Trump hasn’t had a banner first nine months of his presidency. But there is one perk of the job that he will soon experience: appointing the individual who will likely oversee his own tax audit.

On November 12, I.R.S. commissioner John Koskinen’s term will expire, leaving the top job at the agency vacant. Bloomberg reports that Trump has not yet nominated a successor, but that Treasury Secretary Steve Mnuchin has begun the vetting process to replace the Obama appointee with a more amenable candidate. Koskinen famously clashed with Republicans in Congress, who they tried and failed to impeach in 2016 for allegedly mishandling the agency’s targeting of tea party-aligned political groups.

Trump undeniably has a vested interest in naming a friendlier replacement. For starters, the next head of the 80,000-person agency would oversee Trump’s ambitious tax-reform effort—which the president characterized as a “once-in-a-generation opportunity.” They will also oversee the audit of Trump’s tax returns, which he has refused to release to the public. Trump has previously claimed that he has been audited “every year—twelve years or something like that.” That scrutiny won’t let up, either: as president, the law requires that Trump be audited every year that he is in office.

Perhaps most notably, Koskinen’s replacement will also likely have to work with special prosecutor Robert Mueller in the ongoing Justice Department probe into whether the Russian government colluded with the Trump campaign. On Tuesday, CNN reported that the I.R.S. has begun sharing information with Mueller’s team about Trump’s former campaign chairman Paul Manafort and former National Security Adviser Mike Flynn, who have emerged as key figures in the ongoing investigation.

Of course, whomever Trump appoints to the soon-to-be vacated post will require Senate confirmation and any perceived attempt by the Trump administration to influence the Russia investigation through the appointment would be met by pushback from Congress. Not to mention that the sprawling, bureaucratic nature of the I.R.S. makes it difficult to influence the agency. “The career folks at the I.R.S. are not going to let anybody come into the organization, appointee or not, and tell them who and what they have to do in the way of examining someone,” Lawrence Gibbs, who worked at the I.R.S. for 17 years and served as the commissioner in the 1980s, told Bloomberg.