THE JOB of inspector general is often a thankless one, requiring the ability to make unflinching and crucial assessments that are not always well received by colleagues.

The Justice Department employed one of the best for the past decade in the person of Glenn A. Fine, who recently stepped down.

Mr. Fine was instrumental in unearthing problems and identifying solutions in the mammoth agency since joining the IG's office in the mid-1990s. He took over the reins in 2000 and led investigations into all facets of the department's operations.

He documented the FBI's early abuse of national security letters - powerful tools issued without judicial review and used to obtain information from individuals and corporations alike. He later produced an authoritative review lauding FBI leaders for significant improvements. This latter report was credible in part because Mr. Fine did not pull punches in his original criticism.

Other reports followed suit, documenting abuses of some immigrants after the Sept. 11, 2001, terrorist attacks; the Bush administration's politicization of hiring for what should have been non-political posts in the civil rights division and the highly acclaimed honors program; and the alarming lack of preparedness in the event of a domestic attack using weapons of mass destruction.

No one person can effectively police an organization as large as the Justice Department without a dedicated staff. In Mr. Fine's case, that has meant some 440 employees, including lawyers, auditors, law enforcement officials and others. From Republican to Democratic administration, and through controversy over balancing security and civil liberties in an age of terrorism, they maintained a high standard of integrity and fair play.

While other inspectors general have been plagued with accusations of partisanship, Mr. Fine's office has remained above the fray. This may be Mr. Fine's most important legacy and one that should be honored by naming a new chief who will bring the same level of steel and intellect to the job of policing the nation's premier law enforcement agency.