In the 1980s, the crack cocaine epidemic and rising violent crime rates led to mandatory sentencing and massive prison building projects. By the early 1990s, three-strikes-you’re-out laws raced through the country.

Then crime rates began dropping. Everyone took credit. Tough-on-crime folks said mandatory sentences and the threat of lifelong imprisonment scared people straight. Community policing pioneers credited their neighborhood watch programs. One theory was especially controversial. Did increased abortion rates in the ‘70s and ‘80s mean that fewer babies were born into high-risk families and therefore never became teen criminals?

Slowly the debates between the lock-‘em-up folks and the prevention folks faded into the background, replaced first by Y2K hysteria and then by legitimate fears of international terrorism after Sept. 11.

But concern about rising crime rates will return soon to the public debate, predicts syndicated columnist David Broder, who is not known for hysteria over any public issue. FBI Uniform Crime Reports show that in 2006 arrests for murder, robbery, drugs, arson, weapons and vandalism rose, especially among young criminals.

Why? More young people are entering crime age; gangs are infiltrating the immigrant population; the number of people leaving prisons will increase in the next five years and the Internet is opening up new crime arenas. Here’s another possible reason, yet unproved: “iCrime.” The Associated Press reports that the Urban Institute, a Washington think tank, believes iPod thefts have contributed to escalating robbery rates.

Closer to home, Washington State University is worried about its rising violent crime rate. S-R reporter Shawn Vestal recently noted that assaults reported to Pullman police have climbed 41 percent since 2000; disorderly conduct complaints have doubled. And a Spokane Valley couple, who are in their 80s, were recently ambushed in their garage. They escaped with minor injuries, but the brutal assault rattled the neighborhood because that type of violent crime is rare there if not unprecedented.

The challenge now is to look back to recent history and understand what worked against rising crime the last time around. One theory says that all the 1980s-1990s crime-prevention measures coalesced to bring down the crime rate.

So expect calls for tougher sentences and more prisons. But we also need the call for neighbors to look out for neighbors, because crime trends begin at the street level. And we need caring adults to mentor angry and potentially violent young people.

Neighborhood vigilance and a commitment to young people aren’t as expensive as prisons, but they do tap into a community’s social capital. Discovering some more of that social capital might be the bright side of the predicted spike in crime.