U.S. consumers lost a powerful voice for their interests in Washington, D.C. Eugene Kimmelman, President Obama's bulldog on antitrust issues, is moving to another realm of public service.

Kimmelman joined the administration in August 2009 as deputy assistant attorney general in the antitrust division of the Justice Department. He stepped down Friday to work for Global Partners, a human-rights organization, and will open an office in the nation's capital.

Kimmelman was this newspaper's choice in 2010 to lead the new Consumer Financial Protection Bureau. The agency is charged with protecting Americans from the abuses suffered in recent years with mortgages, credit cards, private student loans and debt collection.

Though not eventually selected, he was ideal for the job because of his broad experience in the realm of consumer affairs. Kimmelman was vice president of federal and international affairs at the Consumers Union, the nonprofit publisher of Consumer Reports magazine. He had also served as chief counsel for the antitrust subcommittee of the Senate Judiciary Committee.

Kimmelman knows the law and he knows Capitol Hill. The combination fueled a powerful influence on behalf of consumers.

The Washington Post, which broke the story of his departure, credits him with securing Obama administration opposition to AT&T's bid for T-Mobile. He won a series of conditions to protect competition before the Justice Department approved Comcast's joint venture with NBC Universal.

He was looking at everything from cable deals that might suppress competition from online video providers to the pricing of e-books.

Kimmelman had deep influence because of his knowledge and experience, and a pragmatic streak that allowed him to make deals work with modifications to protect consumers.

He takes those strengths into another volatile realm that will benefit from his capacities.