One year does not a trend make, and so it would be wrong to make too much of the report this week from the U.S. Bureau of Justice Statistics that shows an increase in violent crimes in 2011. However, the fact that this was the first measurable increase in nearly 20 years raises worries that the reduction in crime nationwide may have bottomed out.

Are there things society can do, officially and unofficially, to move the trend downward again? Answering that question requires an understanding of why crime has been dropping steadily since the 1990s, and that isn't easy to do.

Early in the trend, police were trumpeting the elevation of the "broken windows" theory of law enforcement. Simply put, when authorities make an effort to solve the small crimes, such as the breaking of a window, it sends signals that reduce the overall rate of larger crimes. When broken windows are allowed to remain unfixed, people with criminal tendencies get the impression security is lax and the chances of getting caught slim.

Certainly this may have had something to do with crime dropping. Demographics, however, also played a likely roll. The nation is growing older. The median age today is 36.8 years, compared to 27.9 in 1970. Young people, men in particular, are more prone to crime than people who have acquired age and maturity. In addition, the get-tough policies many states and the federal government adopted during the '90s, ranging from three-strikes laws that automatically imposed life sentences on third-time offenders, to minimum-mandatory sentences, have locked many people away. In 2010, 2,226,800 Americans were in state or federal prisons, according to the Bureau of Justice Statistics. Obviously, this has an effect on crime rates, as well.

Success has 1,000 fathers. But those reasons, however effective they may be, don't attack the root causes of crime. The best long-term deterrent is a nation of strong families capable of instilling values in the rising generation. A nation that values its religious traditions, where shared values of honesty, love and respect are taught and elevated as common ideals, will stand a better chance of reducing crime without the added expense of extra prisons.

It's important to examine the statistics released this week. The increase in crime is confined mainly to simple assaults and property crimes such as burglary and theft. Violent crimes — rape, sexual assault, robbery and the use of weapons in a threatening manner — remained about the same. This survey is important because it is based on Census statistics that measure crime from those who are victims. A portion of these victims never report the crimes they have suffered, especially when they involve minor assaults or thefts, and so those crimes would not show up on any survey that measures police case loads.

The report is no cause for immediate alarm. Criminologists are quick to note that 2011 was the second best year for crime in recent history and that it looks bad only in comparison to 2010, which was the best year.

But Americans should not be satisfied that crime rates have leveled off, even if those levels are far lower than during much of the late 20th century. Each crime is a violation of a person's rights, an assault on safety, security and liberty. Policing, like so many other aspects of civil society, is the responsibility of all.