The open exploits of Dowd and other corrupt cops told us as much about the failures of the department’s commanders as they did about its rogue officers. From the top brass down to the patrol officer, willful blindness was often the norm. And New York may not be alone. Police experts across the country have described a similar reluctance among police departments to uncover corruption.

We learned about this problem early in our investigation. While plowing through department documents one night, we received a phone call from a fearful internal-affairs investigator who would identify himself only as ““Mr. G.’’ – and who used a mechanical voice disguiser and pay phone to ensure his anonymity. Weeks later he finally agreed to meet with us – at a hotel outside New York City. Like scores of other officers we later spoke with, he told us that the department often prematurely closed police investigations, denied vital resources to anti-corruption efforts and was more committed to ignoring and concealing corruption than uncovering it.

The problem runs deeper. Corruption flourishes largely because of a police culture that exalts loyalty over integrity. Honest officers are silenced by their fear of ““ratting’’ on another cop no matter how grave the crime. Supervisors often fear the impact of a corruption scandal on their careers more than corruption itself. No institution wants its reputation tainted. But police departments have uniquely powerful incentives to avoid uncovering corruption. Not only do the ensuing scandals embarrass the department and destroy morale and commanders’ careers; they can destroy the public confidence and credibility the police need to fight crime. When jurors disbelieve police testimony and citizens lose faith in their cops, the fight against crime becomes tougher still. Police chiefs thus often believe that fighting crime and police criminality are mutually exclusive.

Anti-corruption strategies must be radically changed so that police have an incentive to effectively police themselves. One solution, proposed by the Mollen Commission and recently adopted by the New York City Council, is a permanent independent ““corruption monitor’’ with subpoena and investigative powers to oversee the department’s efforts. It would be the first of its kind in the nation – and could serve as a model for other cities. The police department would remain responsible for all aspects of fighting corruption. But the monitor would identify shortcomings, and successes, as they occurred, and let the department – and the public – know how well the police were doing. This would replace fear of disclosing corruption with fear of disclosing the department’s failure to combat it.

The monitor would also ensure that departments hold supervisors accountable for maintaining integrity. They would make sure that recruitment, screening and training are effective, and, most important, that honest officers are encouraged to join the fight against corruption.

Twenty years ago, the Knapp Commission found widespread police corruption in New York City. Its solution focused on prosecutions rather than prevention and oversight. But as New York’s recent scandal reveals, that approach failed. No one can better prevent and uncover criminality/ than the police. But without outside pressure, departments will revert to their natural tendency to let their self-policing efforts slide. We believe this monitor will help persuade the vast majority of honest cops – and their commanders – to be allies rather than enemies in the struggle against corruption.