With Americans searching for any shred of good news, it's important to take special note that crime is declining even in the midst of a struggling economy.

Violent crime was down 4.4 percent nationwide in the first half of last year, and property crime was down 6.1 percent, according to the FBI's preliminary 2009 figures. Murders fell by 10 percent, with the largest drop coming in big cities.

Year-end reports bordered on the astonishing in some of those cities, including Minneapolis and New York. Minneapolis recorded just 19 homicides last year, down from 39 in 2008, and a far cry from the 97 killed during the infamous "Murderapolis" crime wave that peaked in 1995. In New York, fewer people were murdered last year, 461, than in any year since 1962. Homicides and other violent crimes also declined in Chicago, Boston, Philadelphia, Atlanta, San Francisco and all but a few other large cities. St. Paul recorded 12 homicides in 2009, down from 18 the year before.

Altogether, the waning violence and mayhem are part of a positive 20-year trend. Since the early- to mid-'90s, murders have declined by a remarkable four-fifths in New York and Minneapolis, and by two-thirds in Los Angeles.

"It is a different world," Los Angeles Police Chief Charlie Beck told the Los Angeles Times. "There was a time when it was the opposite of today -- when it seemed there was no limit on the potential for things to get worse and worse. The whole outlook has shifted now."

The intriguing question is why. Criminology rivals economics as a dismal science, with experts constantly struggling to explain ups and downs. That crime should rise along with unemployment and desperation seemed a logical expectation -- but apparently not.

One sure factor is the decline of gang killings over drug turf. The crack cocaine epidemic that fed so much of the '90s violence has run its course. Longer prison sentences, too, may be keeping kingpins and other major criminals off the streets, helping to make neighborhoods more peaceful. Demographics surely play a part. An aging population leaves fewer potential perpetrators (and victims) of prime criminal age. It may also be that the gangster, as a cultural type, has lost some of his faddish appeal.

Gun enthusiasts claim credit, too, arguing that the rush to buy firearms after President Obama's election deterred crime. (The gun lobby urged a buying spree on fears -- unfounded, as it turned out -- that the new president would restrict handguns and assault rifles.) That scenario is unlikely, however, given that crime declined both in places with strict and lax gun laws.

Our view is that smarter, more proactive police tactics have contributed most to crime's decline. Reforms begun in New York in the 1980s are now routine nationwide. Officers stop known criminals for minor offenses, and guns are often confiscated. Computerized maps predict crime hot spots, and officers are dispatched to flood those zones. Gunfire detectors and cameras help patrol high-crime areas. Closer police-community partnerships have been forged in many cities. Police administrators are held accountable for lower crime numbers.

"Where police chiefs might have been perfectly willing to say, 'It's the economy or something else and there's nothing we can do about it,' their bosses -- mayors and city councils -- now know they can and should expect reductions in crime," Rutgers University criminologist George Kelling told the Los Angeles Times. "There is now a pressure of, 'If you can't get the job done, we'll find someone who can.' "

Two worries linger: the severe budget cuts facing many police forces, and the news media's continuing obsession with spreading fear. To watch or read the news, you'd think that many cities were still in the grip of a frightening crime wave with no end in sight. The numbers tell a different story.