I would like to be remembered as somebody who was deeply and personally engaged with the agencies and their work and not standing separate as an independent force just identifying legal issues and analyzing them in a vacuum without working closely with the ethics community. 

In his resignation letter, Shaub wrote: “The great privilege and honor of my career has been to lead OGE’s staff and the community of ethics officials in the federal executive branch. They are committed to protecting the principle that public service is a public trust, requiring employees to place loyalty to the Constitution, the laws and ethical principles above private gain.”

Shaub continued: “I am grateful for the efforts of this dedicated and patriotic assembly of public servants, and I am proud to have served with them.”

In the buildup to Inauguration Day, the Office of Government Ethics took to Twitter—a favorite platform of Trump’s—to urge the president-elect to divest his business interests to avoid conflicts of interest. It was Shaub, according to an NPR report, who was behind social media posts that appeared to mimic Trump’s distinctive style on Twitter. One tweet read: “Brilliant! Divestiture is good for you, good for America!”

The flare-ups between Shaub’s ethics office and the administration would only intensify after Trump took office.

In recent weeks, Shaub found himself in a standoff with the administration over his request for copies of ethics waivers allowing former lobbyists, lawyers and other appointees to interact with past clients and employers.

The Office of Management and Budget, under director Mick Mulvaney, initially refused to provide those records, prompting Shaub to publish a 10-page letter saying that the Office of Government Ethics expected federal agencies to comply with his request. The White House later released documents showing that 17 appointees had been granted waivers. Shaub remained unsatisfied, taking particular issue with an undated waiver allowing White House officials to interact with the media.

“There is no such thing as a retroactive waiver,” Shaub told The New York Times last month. “If you need a retroactive waiver, you have violated a rule.”

Trevor Potter, president of the Campaign Legal Center, a partner at Caplin & Drysdale and Stephen Colbert’s lawyer, said in a prepared statement Thursday that it is “imperative that we sustain a culture of high ethical standards in our government.”

“Walt, in serving the American public at the OGE under three presidents, has demonstrated the highest level of professionalism and integrity,” Potter said.

Another notable recent hire at the Campaign Legal Center is Paul M. Smith, the former Jenner & Block appellate partner and veteran U.S. Supreme Court advocate. Smith left Jenner in January for a post at the center, where he’ll work on election law litigation.