U.S. seeks to block Arizona law

The Obama administration filed a lawsuit on Tuesday to prevent a law in Arizona from taking effect that would give police the authority to question a person as to whether they are in the country illegally.

The Justice Department asked the U.S. District Court for the District of Arizona for a preliminary injunction to stop the law from taking effect on July 29. The department argues the law is unconstitutional, interferes with the federal government's authority and would create a patchwork of state laws.

"Arizonans are understandably frustrated with illegal immigration, and the federal government has a responsibility to comprehensively address those concerns," Attorney General Eric Holder said in a statement. "But diverting federal resources away from dangerous aliens such as terrorism suspects and aliens with criminal records will impact the entire country's safety."

Reaction to the lawsuit was swift and emotional. "The Obama administration has not done everything it can do to protect the people of Arizona from the violence and crime illegal immigration brings to our state," Arizona Republican Sens. Jon Kyl and John McCain said in a statement. "Until it does, the federal government should not be suing Arizona on the grounds that immigration enforcement is solely a federal responsibility."

But critics of the law celebrated the court challenge.

"The Department of Justice did their job and took a strong stand in defense of the United States Constitution and to protect American citizens," said Ali Noorani, executive director of the National Immigration Forum. "Let me be clear: Arizona's law is the wrong approach, and we fully support the administration's effort to overturn this law."