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Don McGahn is leaving the White House at a critical time for Trump.

President Donald Trump confirmed in a Wednesday morning tweet that the White House’s top lawyer would exit “in the fall.” As Axios reported earlier this morning, he will likely happen sometime after Brett Kavanaugh’s expected confirmation to the Supreme Court next month.

McGahn’s departure comes at a sensitive legal moment for the president. A potential Democratic takeover of the House this November would ratchet up congressional scrutiny of the White House and the counsel’s workload. Trump’s personal lawyers are also negotiating terms for an interview with special counsel Robert Mueller on the Russia investigation. McGahn, who likely witnessed Trump’s efforts to obstruct the inquiry, reportedly participated in more than 30 hours of interviews with Mueller’s team on the subject. Iowa Senator Chuck Grassley, who worked closely with McGahn on judicial appointments, expressed dismay at the news.

The White House counsel’s office represents the office of the presidency and not the president himself, a distinction that Trump has reportedly struggled to appreciate. The New York Times reported in January that Trump ordered the dismissal of Mueller last June, only to back down when McGahn refused to carry out the order and threatened to resign. McGahn’s defiance may have prevented a latter-day repeat of the Saturday Night Massacre, Richard Nixon’s infamous purge of the Justice Department during the Watergate crisis.

According to Axios, the likely frontrunner to replace McGahn is Emmet Flood, a veteran Washington litigator who worked for presidents Bill Clinton and George W. Bush. Flood, who joined the president’s personal legal team earlier this year, reportedly enjoys the confidence of both the president and his West Wing staff for taking a more hardline approach toward Mueller’s inquiry. Keeping that confidence as legal pressures mount on the Trump White House will not be an easy task.