Do politicians affect the murder rate?
According to new American research, the less we trust our politicians, the more likely we are to kill each other.
So how does Ohio State University professor Randolph Roth explain the fact that the homicide figures for England and Wales are the lowest for a generation? Or why today's BBC research suggests 21 fewer teenagers were victims of murder or manslaughter year-on-year? After all, the last 12 months have seen the reputation of our parliamentarians take a battering.
Criminologists have long puzzled over the key factors in a society's murder rate. Professor Roth has tried to take an historical view, analysing the records of tens of thousands of homicides in the United States and Western Europe over the past four centuries. Familiar arguments as to what contributes to the problem simply don't hold up, he claims.
Poverty and unemployment don't correlate with higher murder rates and locking up criminals and the death penalty don't correlate with lower murder rates, he says. Professor Roth believes a far more convincing argument is that "the predisposition to murder is rooted in feelings and beliefs people have toward government and their fellow citizens."
While the first part of his explanation will attract headlines, I suspect it is the second part which is more important. It seems almost self-evident that people kill their fellow citizens more when they respect their fellow citizens less.
To be fair to the professor, he suggests four factors which contribute to lower murder rates:
• a belief that one's government is stable and its justice and legal systems are unbiased and effective
• a feeling of trust in government officials and a belief in their legitimacy
• a sense of patriotism and solidarity with fellow citizens
• a belief that one's position is society is satisfactory and one can command respect without resorting to violence
This is not really about fury over dodgy duck-house receipts or "flipping" second home designation. It is about a broader confidence in the way society is run and an individual's place within it. Violence, it is suggested, is often a consequence of powerlessness - a last resort for those who feel their voice is not being heard.
A look at people's experience of violence as reflected in the British Crime Survey [1.2Mb PDF] suggests that it has fallen from its height in the mid-1990s and has remained broadly flat over the past five years or so.
The biggest falls have been in what is designated "acquaintance" and "domestic" violence - crimes in which the victim knows his or her assailant. If citizens feel secure and respected within their community, perhaps it makes them less likely to lash out.
When it comes to fatal attacks, the latest figures for England and Wales show that the police recorded 648 incidents of homicide in 2008/09, the lowest recorded level in 20 years. The number of attempted murders also decreased from 621 in 2007/08 to 575 in 2008/09.
Since homicide statistics are difficult to refute, the numbers suggest our society is not becoming more violent but less. The BBC figures for a year-on-year fall in homicides involving teenagers reflect a broader picture both in terms of overall violence and juvenile crime.
Last month, the Ministry of Justice reported [86Kb PDF] a big drop in the number of young people entering the criminal justice system for the first time in England.
Even when including those youngsters given a Penalty Notice for Disorder (PND), the rate of 10-17-year-olds receiving their first reprimand, warning or conviction fell by 20.7%.
Further good news is that the level of youth re-offending is at its lowest since records were first collected in 2000, with the rate down by almost a quarter between 2000 and 2007.
Some of these falls may be down to the initiative of youth offending teams, police officers and other agencies. Government ministers may point to this scheme or that policy.
One thing I am reasonably confident about is that the figures have little to do with the current levels of public affection towards members of parliament.