Updated

Now that the Obama administration is suing Arizona over its tough immigration law, some critics are asking why so-called sanctuary cities are getting a pass for ignoring federal immigration law.

More than 50 cities in the U.S provide sanctuaries to illegal immigrants. Supporters of such policies say they want the local police to focus on solving crimes and leave the immigration work to the federal authorities.

"What sanctuary cities are saying is, we are not going to preempt the federal government. It's the federal government's responsibilities," said Rep. Luis Gutierrez, D-Ill.

But Richard Land, the president of Southern Baptist Convention's Ethics and Liberty Commission, said while he supports comprehensive immigration reform, he opposes sanctuary cities.

"We can't have government officials deciding which laws they are going to enforce or not enforce. That undermines the rule of law. We have to have officials who are under the rule of law," he said.

Sanctuary cities are not a new idea. They've been around for decades and no administration -- Democrat of Republican -- has really gone after them.

But the Obama administration is going after Arizona for its new law that permits officers to ask about a person's immigration status during the course of other law enforcement duties, such as a traffic stops. Opponents say the law promotes racial profiling and is unconstitutional. But supporters deny those charges.

"The Arizona law is in compliance with federal law," said Rosemary Jenks, director of government relations at Numbers USA. "The Justice Department should stay out of it. They should be encouraging Arizona to be enforcing the laws. Secondly, they should be enforcing federal immigration law, which means challenging cities and states that have sanctuary policies."

The Justice Department sees it differently, saying Arizona is unconstitutionally interfering with the federal government's role in immigration control.

"There is a big difference between a state or locality saying they are not going to use their resources to enforce a federal law, as so-called sanctuary cities have done, and a state passing its own immigration policy that actively interferes with federal law," Justice spokeswoman Tracy Schmaler said.

But to those who support the Arizona law and oppose the idea of sanctuary cities, that seems like a cop-out.

"The administration has shown again and again it has no intention of enforcing federal immigration laws," Jenks said.