The story about crime and immigration may be different than you've been led to believe:
A crime puzzle: Violent crime declines in America, by Claude Fischer: Violent crime went down in America again last year. According to preliminary statistics from the FBI, the number of violent crimes dropped by about 5 percent from 2008 to 2009. Given population growth, that means that the rate of violent crime dropped even more. (So did property crime.)
This is a puzzle because (a) violent crime is more common among the poor; (b) the percentage of Americans who are poor has been trending up since about 2000; and (c) the economy tanked last year. One would have expected a rise, not a fall, in violent crime.
But this head-scratcher is just part of a larger puzzle – understanding long-term trends in America’s criminal violence.
The most reliable measure of violent crime is the homicide rate. ...
This graph shows the American homicide rate over the last century-plus. ... We see a cyclical pattern, a high plateau in the 1920s and early ‘30s; a rapid drop of more than half to a low point in the late 1950s; then, a sharp rise, more than doubling, by 1980 and 1990; and then what will probably be a drop of nearly half by 2009. These are huge swings. ...
We can put this story into yet greater perspective with the graph below. The line in that graph represents my rough estimate of fluctuations in the U.S. rate of homicide over many more generations... The overall story is that homicide rates declined substantially (as did rates of interpersonal violence of all sorts). ... The graph also shows that progress was hardly uniform, as there were many upswings of violence. ...
Scholars have offered several explanations for the centuries’-long decline of violence in the West. ... How might ... this explain the latest — the post-1990 — downswing in homicide and in criminal violence more generally? The rates are now approaching the level of the least violent era in American history, the late 1950s.
Researchers point to some similar factors, although they disagree about their relative importance. Some stress government authority, namely that longer criminal sentences and the prison-building boom kept many more “bad actors” off the streets longer. Others point to the economic boom of the 1990s, when unemployment, even in poor communities, sunk to low levels. And others argue — although it is difficult to confirm with “hard data” – that a cultural shift occurred, that increasing revulsion toward violence eventually spread into even the most violent communities and corners of the United States.
Recently, scholars have added yet another explanation: Immigration. Cities and neighborhoods that have received the largest influx of immigrants (including Mexican immigrants) have had — despite popular stereotypes to the contrary — the largest drops in criminal violence. (See, e.g., here and here.) Thus, increased immigration may explain part of the crime drop since 1990.
In a wider view, perhaps the more puzzling part of the story is the rapid upswing in violence from around 1960 to 1990 (see first graph above). Two generations of scholars have yet (it appears to me) to satisfactorily explain why that happened. Some of the upswing in crime can be attributed to the baby boom: Put a lot more 15-to-25-year-old males into a society and you will get an upsurge of violence. Some of it has to do with what happened in the black ghettos of the North: The population grew rapidly just when the well-paying blue-collar jobs for men were disappearing. Some of it involved the growing drug trade. And perhaps some of the upswing reflected a short-term cultural shift — maybe the baby boom generation’s rejection of authority — that encouraged violence.
Whatever the reason, the latest news — that violent crime in the U.S., although still high by first-world standards, is trending downward — seems consistent with our longer history. It is the upsurge of violent crime starting in the early 1960s and now ending that remains the larger puzzle.