For Sonoma County, the kidnapping of Polly Hannah Klaas was a moment frozen in time — a staggering blow to the region's sense of security and quality of life.

Most people can still remember where they were when they heard about the abduction of the 12-year-old Petaluma girl 20 years ago today. Still more can recall the fateful moment when they learned that the two-month hunt for the seventh-grader with the infectious smile, a search involving some 4,000 people, was all for naught.

As former Petaluma City Councilman Dave Keller told Staff Writer Mary Callahan, "It's not just a lingering memory. It's kind of your worst nightmare as a parent, and your worst nightmare as a child."

And the culprit, Richard Allen Davis, 59, who remains on Death Row at San Quentin State Prison, was the embodiment of that nightmare.

While the passing of two decades has done nothing to erase the grief, county residents can take some comfort in the changes that have occurred to correct the deficiencies exposed in the hours after Polly was taken at knife point from her home during a sleep-over with friends.

One major deficiency concerned communications. When two sheriff's deputies encountered Richard Allen Davis late on Oct. 1, 1993 on a remote section of Pythian Road east of Santa Rosa, they were unaware that an abduction had occurred just an hour earlier. Although an alert had gone out, the deputies were using a different radio channel than the one used by Petaluma police. So they let him go.

Although investigators believe Polly was probably already dead at that point, the missed connection remains a disturbing factor in this narrative. But that flaw later led to significant improvements in inter-department communications and the creation of Child Abduction Response Teams, which now help public safety agencies work together to handle similar high-profile cases.

Second, the case also helped build public support for creation of the Amber Alert child abduction system which is used to spread news quickly on everything from radio stations to electronic billboards on highways when a child abduction occurs.

The Polly Klaas case also contributed to the creation of Megan's Law, which opened up public access to information about where registered sex offenders live.

But the most significant change was rooted in the general outrage that Richard Allen Davis was allowed to be free at all that night two decades ago. A twice-convicted kidnapper, Davis had a long criminal history including violent attacks on women. He had spent most of his adult life behind bars but had recently been paroled to a Bay Area safe house. After the murder, California passed the "three strikes" law that requires life-long sentences after a trio of felony offenses.

Because the "three strikes" law was often cited as one of the primary causes for the state's prison overcrowding problems, Californians last year voted to scale it back by exempting nonviolent, lesser offenders from life sentences. It was a needed change, and one that's shown no added risk to public safety.

The loss of Polly Klaas will remain a parents' worst nightmare. But parents can take some comfort in knowing that stranger abduction remains a rare occurrence. And if and when it does occur, the state — as well as the rest of the nation — is far better prepared to respond.