What is the intersection of crime and immigration? I can’t answer that definitively, but I know that there is no more hotly contested issue in Southwestern policy debates.

Last week, I attended an event where an attorney pointed to skyrocketing crime rates as a reason that the Arizona governor had virtually no choice in whether to sign SB1070, the state’s new restrictive criminal law.

But news reports—and Department of Justice statistics—indicate a trend in the opposite direction. And if crime (except on Wall Street) is going down, then where’s the fire? I mean, there may be a lot of reasons to seek comprehensive immigration reform, but should crime be touted as one of them?

(That’s not to say that there are no crimes affiliated with illegal immigration. This spring’s death of an Arizona rancher—if it turns out to have been by an immigrant—is one of the worst examples. Overall, though, the trend does not seem to be increasing.)

Q: However, for argument’s sake (the lawyer’s favorite phrase), let’s say that there is crime and that there is illegal immigration. How are they connected?

A: Not as handily as you might assume, at least according to Tim Wadsworth, an assistant professor of sociology at the University of Colorado at Boulder. His findings are, for many people, counterintuitive:

“Cities that experienced greater growth in immigrant or new-immigrant populations between 1990 and 2000 tended to demonstrate sharper decreases in homicide and robbery,” Wadsworth writes. “The suggestion that high levels of immigration may have been partially responsible for the drop in crime during the 1990s seems plausible.”

To read more about his hypothesis, click here.

There is more news from the University of Colorado here.