Thursday, Justice Department lawyers asked a federal judge in Phoenix to block the law before it takes effect next Thursday. Those in favor of the law say illegal immigration leads to more crime. But does it?
In Pima County, Arizona, sheriff's deputies patrol for people crossing the border illegally from Mexico.
"We are encountering folks who have warrants out for their arrests, deported felons," said Sgt. Robert Krygier.
It's a fact of life here that frightens and infuriates many Arizonans.
CBS News correspondent Bill Whitaker reports supporters of the new law point to the recent murder of rancher Robert Krentz. Investigators say his killer snuck in from Mexico. Arizona governor Jan Brewer says Mexican drug cartel-style violence is crossing the border too.
"Our law enforcement agencies have found bodies in the desert, either buried or just lying out there, that have been beheaded," Gov. Brewer said.
In Pima County, Sheriff Clarence Dupnik said not only is there no evidence of beheadings, but "the border is more secure now that it's ever been."
Murder? Burglaries? Rape? The major crimes? Up or down on the border?
"They're down," Dupnik said. "Violence in the cities is down."
According to the FBI, that's true across the southern border this decade. In San Diego violent crime is down 17 percent. In El Paso, Texas violent crime down 36 percent - it sits right across from Juarez, Mexico, one of the deadliest cities on earth. In Phoenix major crime has dropped 10 percent from 2000 to 2009.
West along the border in Nogales, Arizona, Chris Ciruli said it's a "safe environment."
Ciruli, a third-generation produce distributor, said it's as safe as it was 20 years ago. One reason? "We're definitely seeing a lot more Border Patrol over the last few years."
Border Patrol Chief Victor Manjarrez is in charge of the 262-mile Tucson sector that covers Nogales. Thirty-three thousand agents patrol today, up from 1,500 a decade ago. When it comes to crime, Manjarrez said the rhetoric doesn't match reality.
No one is downplaying the magnitude of the problem. Officers say thousands of immigrants and smugglers still cross the border illegally into Arizona every day.
Illegal immigrants are just seven percent of Arizona's population,but make up nearly 15 percent of the state's prison population. They represent 14 percent of all inmates jailed for manslaughter and murder, and 24 percent of inmates on drug charges - troubling to many Arizonans - even if the overall crime rate is down.
Protestors for and against the law are outside the court. Inside court, the judge said she is skeptical that the law is constitutional. She's expected to rule within days.