There is a new study out claiming that lead levels are responsible for crime. They compare lead levels with crime rates 23 years later (i.e. after the criminals grew up eating, drinking and breathing the lead), and found a high correlation.
It is well known that lead lowers IQ, damaging learning and memory, as well as causes brain, kidney and cardiovascular damage. Now, some think it encourages violent actions as well.
I myself feel that crime is more likely to be related to legalized abortion, as unwanted children get a bad upraising and that leads to crime. Among other things, I think China would have had a higher crime rate as they are a late comer to anti-lead laws, while they have family planning under strict government control..
But assuming that the studies are at least partly correct and lead plays a significant role in crime, then the Democrats just took back the pro-law and order crown.
Much of our anti-lead laws were enacted during Nixon's presidency- both the Clean Air Act and the Lead Based Paint prevention act. But they were pushed by Democrats, particularly Senator Edmund Muskie, who ran as VP against Nixon. He was one of the first environmentalists in the senate.
Then in 1990,,the Clean Air Act was amended (by Democrats), and again in 2008, under Obama, the EPA finally tightened lead rules.
If this study is true than the Democratic Party is and always has been the real anti-crime party.