Protesters march in front of the Arizona House building in Phoenix.

Protesters march in front of the Arizona House building in Phoenix. (Associated Press)


The planned lawsuit was confirmed to The Associated Press by a Justice Department official with knowledge of the plans. The official didn't want to be identified before a public announcement planned for later Tuesday by Attorney General Eric Holder and Homeland Security secretary Janet Napolitano, a former Arizona governor.

The lawsuit will argue that Arizona's law requiring state and local police to question and possibly arrest illegal immigrants during the enforcement of other laws such as traffic stops usurps federal authority.

The government will likely seek an injunction to delay the July 29 implementation of the law until the case is resolved.


State Sen. Russell Pearce, the principal sponsor of the bill co-sponsored by dozens of fellow Republican legislators, denounced the reported lawsuit as "absolute insult to the rule of law" as well as to Arizona and its residents.

"It's outrageous and it's clear they don't want (immigration) laws enforced. What they want is to continue their non-enforcement policy," Pearce said. "They ignore the damage to America, the cost to our citizens, the deaths" tied to border-related violence.

State Rep. Kyrsten Sinema, a Phoenix Democrat who opposes the law, said the suit should help settle questions over what states can do when they don't think federal laws are being adequately enforced.

"I hope this galvanizes Congress to gain the moral courage they need to address this (immigration) crisis," Sinema said.


Prior to seeing the lawsuit or receiving any official notification, Gov. Jan Brewer's spokesman called the reported decision to sue "a terribly bad decision."


Three of the five Democrats in Arizona's congressional delegation, who are facing tough re-election battles, had also urged Obama not to try to block the law from going into effect.

Republican Sens. Jon Kyl and John McCain of Arizona also lashed out at the administration's decision, saying "the American people must wonder whether the Obama Administration is really committed to securing the border when it sues a state that is simply trying to protect its people by enforcing immigration law."

The law requires officers, while enforcing other laws, to question a person's immigration status if there's a reasonable suspicion that they are in the country illegally.



"As other states and localities go their own ways, we face the prospect that different rules for immigration will apply in different parts of the country," Obama said. "A patchwork of local immigration rules where we all know one clear national standard is needed."



Arizona State University constitutional law professor Paul Bender said the federal government's involvement throws a lot of weight behind the argument that federal law pre-empts Arizona's measure.

"It's important to have the federal government's view of whether state law is inconsistent with federal law, and they're the best people to say that," Bender said.

Kris Kobach, the University of Missouri-Kansas City law professor who helped draft the Arizona law, said he's not surprised by the Justice Department's challenge but called it "unprecedented and unnecessary."

He noted that the law already is being challenged by the


"The issue was already teed up in the courts. There's no reason for the Justice Department to get involved. The Justice Department doesn't add anything by bringing their own lawsuit," Kobach said in an interview.