(Reuters) -The U.S. Securities and Exchange Commission (SEC) has tapped a senior military judge to head up its enforcement director, in what legal sources said was an unconventional pick for the top job policing Wall Street.

Margaret "Meg" Ryan, a senior judge of the United States Court of Appeals for the Armed Forces, will take up the position on September 2, the SEC said in a statement on Thursday. In the new role, she will lead the 1,400-person division tasked with policing U.S. securities markets.

Ryan was previously on a list of potential nominees for the Supreme Court that Republican Donald Trump published in 2016 while on the campaign trail ahead of his first presidential term. She previously clerked for Supreme Court Justice Clarence Thomas and former judge Michael Luttig, another well-known conservative.

Previously an active-duty U.S. marine, Ryan deployed to the Philippines and Saudi Arabia. In 2006, Republican President George W. Bush nominated her to be a judge on the U.S. Court of Appeals for the Armed Forces.

Sam Waldon, who has been acting director of enforcement since January, will return to his previous role as chief counsel for the division, the SEC said.

(Additional reporting by Ryan Patrick Jones and Bhargav Acharya in Toronto and Douglas Gillison in Washington;)