I have been observing crime and policing in New Haven for four years now. So, as this academic year and this column ease off into the sunset, it’s time to review the recent history of city policing — and especially to recall one of its most successful, overlooked leaders.

It has been a tumultuous time for the city. In four years, four chiefs have led the New Haven Police Department, each with a different style, strategy, demeanor and vision. The leadership was sometimes effective, sometimes incompetent, but never steady.

Crime, too, has fluctuated wildly in the past few years. Though the overall rate has declined fairly steadily and slowly, violence — particularly murder — has reached record highs and more tolerable lows. But the core reality that there is too much crime still looms over life in many of New Haven’s neighborhoods. And that fact, unfairly magnified, continues to infect the way many Yalies look at the city and the way many across the country look at Yale.

Police and city officials have the power to change that reality with the right approach. All too often, however, a sincere effort at self-examination is stifled by the unwarranted optimism of the news conference or the empty promise of the press release. It is now popular among officials to discuss the lessons of the city’s successful policing practices of the 1990s, rather than the more complicated lessons of the past few years. Recent history is inherently fraught with biases, passions and controversies and is therefore more painful and difficult to examine. But those more recent events provide crucial insight and guidance for effective police leadership.

The department’s current leaders should remember that recent progress has been built on the back of former chief James Lewis. A veteran police chief who had been brought out of retirement in mid-2008, Lewis restored order to an NHPD still reeling from a corruption scandal that saw its narcotics unit disbanded for over a year. Lewis was a quiet, friendly man from Wisconsin and began his tenure by going to the start of each shift until he had shaken hands with and met every member of the force — approximately 400 officers.

But he expected much from men and women in uniform: When officers misbehaved, he recommended the strictest sanctions. Perhaps most importantly, Lewis revamped the city’s drug unit so that it operated in both the most effective and community-friendly way: by focusing on drug dealers who were dealing out the most violence to neighborhoods. Crime fell by about 10 percent during his last year in office. Most of the department loved him; even the police union threw some compliments his way. What he was not was a pal of Mayor John DeStefano Jr.: In 20 months, Lewis met alone with him a grand total of two times.

The new chief, Dean Esserman, has mostly carried on the legacy Lewis left, but with some significant gaps. Esserman believes in the type of aggressive, targeted operations typified by the drug unit under Lewis. But just three weeks after Esserman took office, the innovative officer whom Lewis had appointed to lead the unit — who by then had risen to the rank of assistant chief — announced his retirement. The officer said it was for personal reasons, but departmental rumors said it was because of a conflict between him and Esserman. If true, the incident would be typical of Esserman: a smart, hard-charging leader who is not afraid to step on other people’s toes. In his previous posting, he was suspended for a day after threatening to dump coffee on a sergeant.

There are already hints of similar strong-arm tactics that have alienated some officers here. Chief among them was Esserman’s move to dump the department’s leadership, even one assistant chief widely liked in the community. In his quest to return the department to the 1990s, Esserman should not disregard the experience of the officers who have served since then. Lewis knew that morale matters.

As for mayoral involvement, Esserman is a pal of the mayor’s. There’s no harm in that necessarily, but we should remember that the police leadership is still largely controlled by the mayor. Last year, that meant that DeStefano was able to fire the previous police chief in the middle of a heated election, lie about it and keep it secret for several days and then unilaterally hire Esserman before anyone in the city had a chance to discuss what should be done. Conflicts will arise, and when they do, Esserman should again think of the integrity and independence of Lewis and remember that he serves the residents of New Haven first, the mayor second.

Colin Ross is a senior in Berkeley College. This is his last column for the News. Contact him at colin.ross@yale.edu.