In Virginia, a three-year study of Prince William County's controversial illegal immigration policy concludes that it has reduced the number of illegal immigrants in the county -- but has also had some unintended consequences.
The policy requires police officers to examine the citizenship status of every person they arrest.
Researchers from the University of Virginia and the Police Executive Research Forum say it was smoothly implemented, and has led to thousands of undocumented immigrants leaving Prince William.
County Board Chair, Corey Stewart, says the study affirms what local leaders already believed.
"We've come up with a policy that is practical to enforce, is not overburdening our police department, and is having a positive impact on our community," Stewart says.
Stewart says it's also keeping Prince William's crime rate low.
But researchers conclude the policy has had no discernible effect on overall crime trends, though they did find decreases in assaults and hit and run accidents.
Stewart says he'll forward the study to lawmakers in Richmond as evidence that the policy should be adopted statewide.
John Steinbach, with the local group Mexicans Without Borders, opposes the policy.
He says many Hispanics now see Prince William as an unfriendly place.
"If your purpose is to terrorize the community, to break up families, to incite hatred, then by all means -- this is a wonderfully successful resolution," Steinbach says.
The study shows that while the D.C. metro area has seen a 19 percent jump in its Hispanic population, Prince William has seen less than a 4 percent bump.