Phoenix (AP) - The federal lawsuit against Arizona's tough new immigration law focuses heavily on a question that has been in the spotlight repeatedly the past decade and dates back to the Founding Fathers: The right of the government to keep states from enacting laws that usurp federal authority.
The lawsuit filed in Phoenix federal court on Tuesday sidestepped concerns about the potential for racial profiling and civil rights violations most often raised by immigration advocates. Experts said those are weaker arguments that don't belong in a legal challenge brought by the White House to get the measure struck down.
Instead, the suit lays out why the government believes that immigration laws passed by Congress and enforced by a range of federal agencies must take precedence to any passed by a state Legislature.
The Arizona law requires officers, while enforcing other laws, to question a person's immigration status if there's a reasonable suspicion that they are here illegally, such as speaking poor English, traveling in an overcrowded vehicle or hanging out in an area where immigrants typically congregate.
The law also makes it a state crime for legal immigrants to not carry their immigration documents.
Backers of the law say the crackdown is a necessary tool to keep illegal immigrants out of Arizona and combat problems such as drug trafficking, murders and violent kidnappings that have become so common in a state that is home to an estimated 460,000 undocumented residents.
The federal government will ask a judge to grant an injunction to block the law from taking effect on July 29.
The arguments will focus on a core constitutional concern -- balancing power between the states and the federal government. More specifically, the issue centers on the long-running "pre-emption" legal argument that says federal law trumps state law.
"The nation's immigration laws reflect a careful and considered balance of national law enforcement, foreign relations, and humanitarian interests," the suit says.
The lawsuit goes on to say that a "state may not establish its own immigration policy or enforce state laws in a manner that interferes with the federal immigration laws. The Constitution and the federal immigration laws do not permit the development of a patchwork of state and local immigration policies throughout the country."
Backers of the law say that Arizona will have some strong arguments in its favor in fighting the lawsuit.
Kris Kobach, the University of Missouri-Kansas City law professor who helped draft the Arizona law, has said the state law is only prohibiting conduct already illegal under federal law. And Harvard Law School professor Gerald Neuman believes Arizona could make a compelling legal argument that it has overlapping authority to protect its residents.
But courts have ruled that under the Supremacy Clause of the Constitution, any state law that conflicts with a federal law is pre-empted. Federal law, the framers said, "shall be the supreme law of the land."
The pre-emption tactic has been successfully used by the federal government on several occasions over the years, including by the Bush administration to limit product liability lawsuits. The government also used it to overturn bans on military recruiters passed by liberal California towns.
Federal courts have invoked the Supremacy Clause on immigration issues as well. For example, a federal judge in 2008 struck down a Dallas suburb's ordinance that banned apartment rentals to illegal immigrants, saying the U.S. government has the ultimate authority to enforce immigration laws.
Within months of taking office, the Obama White House directed department heads to undertake pre-emption of state law only with full consideration of the legitimate prerogatives of the states. The 2009 directive was aimed at reversing Bush administration policy which had aggressively employed pre-emption in an effort to undermine a wide range of state health, safety and environmental laws.
Despite the precedent, that doesn't mean the lawsuit is a sure winner, or that state officials don't believe they can pass laws that head into federal turf.
In fact, efforts by many states trying to block the nation's new health care law run headlong into the Constitution's Supremacy Clause. But immigration is one area where federal authority has generally been upheld.
"Immigration has traditionally and constitutionally been the historic preserve of the federal government, and there are cases going back to the late 19th century that say as much," said Peter Spiro, a constitutional law professor at Temple University who has studied immigration law extensively. "So the Obama Administration has a lot to work with in filing this claim, and the fact that the claim is filed by the administration adds credibility ... and increases the chances that law will be struck down on pre-emption grounds.
"That said, it not by any means a slam dunk," Spiro said.
Regardless of how the case is determined at the district court level, it will likely be appealed. The U.S. Supreme Court is already set to hear an Arizona immigration case in the fall when it takes up a challenge to a 2007 state law punishing employers who knowingly hire illegal immigrants.
If the high court doesn't issue a broad ruling on states' rights to implement laws on immigration in that case, prepare to see the case filed Tuesday make to the justices, Spiro said.
"It's clearly an important case. The Arizona law is unprecedented in its aggressive posture towards illegal immigrants. It's an important issue federally, really, that's the way the administration is framing it. They say the states do not have this kind of role as far an immigration legislation."
Associated Press Writer Jonathan J. Cooper contributed to this report.
The federal lawsuit against Arizona's tough new immigration law focuses heavily on a question that dates back to the Founding Fathers: The right of the government to keep states from enacting laws that usurp federal authority.