A top U.S. ethics official, who has clashed repeatedly with the Trump administration, announced his resignation on Thursday.

Walter Shaub, the director of the Office of Government Ethics, was due to step down in January 2018. But in a letter to the White House on Thursday, Shaub said he would leave the office on July 19.

“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,” Shaub wrote. “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 fought to force the White House to release ethics waivers that document the potential conflicts of interest of executive branch officials. The White House had attempted to keep the documents private. Shaub also criticized President Donald Trump’s handling of his business empire, saying he had not done enough to prevent conflicts.

Shaub will join the Campaign Legal Center, a non-partisan advocacy group that focuses on voting rights and campaign finance issues.

“I have had the honor and privilege of serving the American public at the U.S. Office of Government Ethics under three presidents – George W. Bush, Barack Obama and Donald Trump,” Shaub told CLC. “In working with the current administration, it has become clear to me that we need improvements to the existing ethics program. I look forward to working toward that aim at Campaign Legal Center, as well as working on ethics reforms at all levels of government.”