The staff director and chief counsel of the independent Office of Congressional Ethics in the House, Leo J. Wise, is stepping down in November to join the United States Attorney's Office in Maryland and perhaps sidestep an inevitable political fight over the future of the ethics office.

The office was created by Nancy Pelosi, the San Francisco Democrat, in 2008 after she became speaker and promised to "drain the swamp that is Washington." But it has been controversial from the start, and Ms. Pelosi struggled to get enough votes to create the independent watchdog.

The Office of Congressional Ethics, a small group of lawyers led by Mr. Wise and overseen by a six-member board, operates independently of the Committee on Standards of Official Conduct, known, for short, as the ethics committee, which is controlled by members of Congress.

Ms. Pelosi had hoped that a separate ethics office, after numerous scandals embroiling both parties, would send a message that Congress was not just trying to police itself but was open to an independent monitor.

But lawmakers quickly complained that the ethics office was opening cases in response to frivolous allegations. Most of the cases brought by Mr. Wise and his office were ultimately dismissed by the Committee on Standards of Official Conduct, which retains the power to formally charge lawmakers with wrongdoing and recommend disciplinary action.

Defense lawyers complained that the ethics office often ignored rules. One such lawyer called it "a rogue operation that needs to be shut down."

Among the lawmakers angry at the new office were 20 members of the Congressional Black Caucus who urged that the office be prohibited from initiating its own inquiries unless a sworn complaint was filed by a person with direct knowledge of the alleged wrongdoing. The black caucus members urged that the office's powers also be restricted by prohibiting the release of most investigative reports. The ability to release such reports, even if the ethics committee refused to take up a case, proved to be one of the independent ethics office's most useful tools.

The complaints from the black caucus were spurred because of a large number of investigations directed at black lawmakers that seemed disproportional given that there are relatively few black members of the House.

Republicans have also sharply criticized the ethics office, and Ms. Pelosi for her handling of it. If Republicans win a majority in the November elections, they could well move to abolish the office, and Mr. Wise's resignation seemed designed to avoid being ensnared in such a development. Mr. Wise is a Democrat.

In a statement, Mr. Wise said: "I'm proud of what we accomplished. It was an honor to help build the O.C.E. and lead it through its first Congress."

Mr. Wise had worked at the Justice Department before joining the new ethics office. He graduated from Harvard Law School and was a member of the team that won convictions of the Enron executives, Ken Lay and Jeffrey Skilling.

Former Representative David Skaggs of Colorado, who is chairman of the board that oversees the ethics office, said that a new acting staff director would be named shortly.