By Jerry Markon and William Branigin
Washington Post Staff Writer
Tuesday, July 6, 2010; 5:02 PM

The Justice Department filed suit Tuesday against Arizona, charging that the state's new immigration law is unconstitutional and requesting a preliminary injunction to stop the legislation from taking effect.

The lawsuit says the law illegally intrudes on federal prerogatives, invoking as its main argument the legal doctrine of "preemption," which is based on the Constitution's supremacy clause and says that federal law trumps state statutes. The Justice Department argues that enforcing immigration laws is a federal responsibility and says an injunction is needed to prevent "irreparable harm" to the United States.

But the filing also asserts that the Arizona law would harm people's civil rights, leading to police harassment of U.S. citizens and foreigners. President Obama has warned that the law could violate citizens' civil rights, and Attorney General Eric H. Holder Jr. has expressed concern that it could drive a wedge between police and immigrant communities.

"Arizona impermissibly seeks to regulate immigration by creating an Arizona-specific immigration policy that is expressly designed to rival or supplant that of the federal government," the Justice Department says in its legal brief. "As such, Arizona's immigration policy exceeds a state's role with respect to aliens, interferes with the federal government's balanced administration of the immigration laws, and critically undermines U.S. foreign policy objectives."

It adds that the law "does not simply seek to provide legitimate support to the federal government's immigration policy, but instead creates an unprecedented independent immigration scheme that exceeds constitutional boundaries."

The Justice Department argues that the law would burden federal agencies, diverting resources from the pursuit of people implicated in terrorism, drug smuggling, gang activity and other crimes.

"The law's mandates on Arizona law enforcement will also result in the harassment and detention of foreign visitors and legal immigrants, as well as U.S. citizens, who cannot readily prove their lawful status," the department said in news release.

But Republican lawmakers, state officials and defenders of the Arizona law promptly condemned the lawsuit.

John McCain and Jon Kyl, Arizona's two Republican senators, issued a joint statement saying it was "far too premature" for the Obama administration to challenge the law because it has not yet been enforced. It is scheduled to take effect July 29.

"Moreover, 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 statement said. The 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," McCain and Kyl charged. "Until it does, the federal government should not be suing Arizona on the grounds that immigration enforcement is solely a federal responsibility."

To support its case, Justice included declarations from Arizona law enforcement officials, including the police chiefs of Phoenix and Tucson, saying that the law would hamper their ability to effectively police their communities. The officials said crime victims or witnesses would be less likely to cooperate with law enforcement and that officers would have to be reassigned from critical areas to implement the legislation.

"Arizonans are understandably frustrated with illegal immigration, and the federal government has a responsibility to comprehensively address those concerns," 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. Setting immigration policy and enforcing immigration laws is a national responsibility. Seeking to address the issue through a patchwork of state laws will only create more problems than it solves."

Department of Homeland Security Secretary Janet Napolitano said the administration is "actively working with members of Congress from both parties to comprehensively reform our immigration system at the federal level because this challenge cannot be solved by a patchwork of inconsistent state laws, of which this is one." She said that as governor of Arizona from 2003 to 2009, she vetoed several similar pieces of legislation "because they would have diverted critical law enforcement resources from the most serious threats to public safety and undermined the vital trust between local jurisdictions and the communities they serve."

The federal lawsuit will dramatically escalate the legal and political battle over the Arizona law, which gives police the power to question anyone if they have a "reasonable suspicion" that the person is an illegal immigrant. In addition to Obama and Holder, the measure has drawn words of condemnation from civil rights groups and has prompted at least five other lawsuits. Arizona officials have defended the law and urged the Obama administration not to sue.

Secretary of State Hillary Rodham Clinton first revealed last month that the Justice Department intended to sue Arizona, and department lawyers have been preparing their case.

The case was filed in federal court in Phoenix. A preliminary injunction halting the legislation from taking effect later this month would have to be issued by a judge. Arizona Gov. Jan Brewer (R) signed the law in April.

The preemption doctrine has been established in Supreme Court decisions, and some legal experts have said such a federal argument likely would persuade a judge to declare the law unconstitutional.

But lawyers who helped draft the Arizona legislation have expressed doubt that a preemption argument would prevail.

Brewer's spokesman, Paul Senseman, called the Justice Department's lawsuit "a terribly bad decision," the Associated Press reported.

"Arizona obviously has a terrible border security crisis that needs to be addressed, so Gov. Brewer has repeatedly said she would have preferred the resources and attention of the federal government would be focused on that crisis rather than this," Senseman said.

State Sen. Russell Pearce, the principal sponsor of the Arizona law, denounced the lawsuit as an "absolute insult to the rule of law" as well as to Arizona and its residents, AP reported.

"It's outrageous, and it's clear they don't want [immigration] laws enforced," he 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 believe federal laws are not being adequately enforced. She said she hopes the issue "galvanizes Congress to gain the moral courage they need" to address the immigration crisis, AP reported.

Among groups applauding the lawsuit Tuesday was the American Immigration Council, which said the government was taking an important step to reassert federal authority over U.S. immigration policy.

"America can only have one immigration system, and the federal government must make clear where states' authority begins and where it ends," the group said.

The liberal Center for American Progress said in a statement: "States can't make up their own immigration laws any more than they can print their own money or enter into treaties with foreign countries." While a law allowing local police to check people's immigration status "might have initial appeal," it said, many law enforcement do not want such authority, fearing that it will lead to racial and ethnic profiling.