Interim Heads Increasingly Run Federal Agencies

By PHILIP SHENON

WASHINGTON, Oct. 14 — For now, the most powerful law enforcement official in the federal government is a 47-year-old lawyer little known outside Washington.

Or inside Washington, for that matter.

He is acting Attorney General Peter D. Keisler, who is running the Justice Department until a new attorney general is confirmed by the Senate to replace Alberto R. Gonzales. Mr. Keisler had been in charge of the department’s civil division.