Ellis said in his letter that Nakasone had declined to meet with him to “resolve any concerns you might have related to my selection” as general counsel, adding that his lawyer had also requested “information so I could help address any misunderstandings or concerns.”
The NSA declined to comment to CNN on Ellis’ resignation.
Ellis had been put on administrative leave the day President Joe Biden took office — just a day after he started as the NSA’s top lawyer — because his appointment had become the subject of a Department of Defense inspector general investigation, a source familiar with the investigation told CNN at the time.
The last-minute installation of Ellis, a former Republican operative, drew considerable scrutiny because the role of general counsel at the country’s largest intelligence agency is a civil service position, not a political role, meaning it could have been difficult for the Biden administration to remove Ellis.
The strategy of trying to install political loyalists into career positions is known as “burrowing” in the government.
House Speaker Nancy Pelosi, who had called for a probe into his selection in January, called Ellis’ appointment “highly suspect” and argued it represented a “disturbing disregard” for the country’s national security.
Before joining the Trump administration, Ellis served as the head counsel to California Rep. Devin Nunes, a Republican who was one of Trump’s staunchest supporters. He then became a lawyer with the National Security Council, refusing to testify as part of the House’s 2019 impeachment inquiry. In March 2020, Ellis became the senior director for intelligence on the NSC, joining other Trump loyalists in key intelligence positions.
CNN’s Zachary Cohen and Paul LeBlanc contributed to this report.