WARMING TO one of his favorite themes the other night, CNN's Lou Dobbs repeatedly invoked the phrase "criminal illegal aliens" as he did his best to feed the stereotype that illegal immigrants drive up crime. Dobbs's relentless spleen on this subject has, of course, won him a following. Seal-the-borders nativism won't get anyone elected president -- just ask ex-GOP candidates Tom Tancredo, Mitt Romney, and Rudy Giuliani -- but there is no denying it's good for TV ratings.
Fortunately, politicians and television personalities aren't the only people interested in immigration and crime. Consider a new study from the Public Policy Institute of California, which offers significantly more substance on the topic than anything you're likely to encounter on cable TV or in the presidential campaign.
The paper, by economists Kristin F. Butcher and Anne Morrison Piehl, assesses the impact of immigration on crime by analyzing data from California, which has by far the nation's largest population of prison inmates: One-eighth of all state prisoners in the United States are incarcerated in California, as are 30 percent of all inmates who are not American citizens. What Butcher and Piehl demonstrate is that immigrants, far from being more likely to end up behind bars, are dramatically less likely to do so.
The numbers are striking: While immigrants (legal and illegal) account for 35 percent of California adults, they represent just 17 percent of the state's prisoners. Men born in the United States are incarcerated in California prisons at more than 2-1/2 times the rate of foreign-born men. Within the age group most often involved in crime (ages 18 to 40), US natives -- astonishingly - are 10 times more likely to be in prison or jail than immigrants (4.2 percent of the former are in correctional institutions, and just 0.42 percent of the latter). Even when the focus is narrowed to inmates who were born in Mexico and are not citizens -- the demographic group most likely to include illegal aliens -- the rate of incarceration is only one-eighth that of men born in the United States.
Butcher and Piehl also compared crime rates among California cities. They found that the cities with greater numbers of recently arrived immigrants have lower crime rates, while cities with fewer immigrants experience higher levels of crime.
"Altogether, this evidence suggests that immigrants have very low rates of criminal activity in California," the researchers write -- a finding "consistent with national studies on immigration and crime, which also find low rates of criminal activity for the foreign-born." Butcher and Piehl address the seemingly irreconcilable statistic that nearly one-fifth of federal prison inmates are illegal immigrants. In truth, they explain, there is no contradiction: Since persons arrested for immigration violations are automatically transferred to federal facilities, noncitizens are disproportionately represented among federal inmates. In any case, the federal prison population comprises only 8 percent of the total number of prisoners nationwide.
But you don't have to pore through think-tank studies to recognize that immigration, illegal or otherwise, doesn't drive the US crime rate.
Over the last dozen or so years, the number of illegal immigrants in the United States has doubled to an estimated 12 million. Those same years saw a dramatic nationwide fall in violent crime and property crime. Similarly, the surge in illegal immigration didn't prevent welfare caseloads from falling or millions of new jobs from being created.
Americans may not have the statistics at their fingertips, but most of them understand that immigrants, even those who enter the country without permission, are here not to make trouble but to make a better life for themselves and their families. Yes, Dobbs has his loyalists; in a nation of 300 million people, you can find an audience to whoop it up for just about any cause. But far more Americans recognize that demonizing illegal immigrants is as bootless as it is mean. In opinion polls, only a minority of respondents say illegals should be forced to leave; the consistent majority preference is that illegal immigrants be given a way to earn American citizenship.
The most distressing spectacle of the 2008 presidential race so far was the attempt by Tancredo, Romney, and Giuliani to win their party's nomination through a Dobbsian attack on illegal immigrants. And the most encouraging development? The Republican Party's rejection of that appeal and its elevation of Senator John McCain, who had steadfastly refused to take part in the immigrant-bashing.
So chalk one up for American common sense. The anti-immigration rabble-rousers haven't disappeared -- but none of them will be the next president of the United States.
(Jeff Jacoby is a columnist for The Boston Globe.)