Lawyers for each side butt heads in Washington in Arizona vs. United States on April 25, the last argument day of the term. A loss for the Obama administration in the Arizona case, like a putative loss in the federal healthcare law challenge, would be a body blow to President Obama's re-election efforts.
Justice Elena Kagan has withdrawn from the Arizona case, citing her previous work as U.S. solicitor general, lowering the odds for an administration victory.
Meanwhile, what's going on back in Arizona? The squabbles at the high court seem to be mirrored in clashes in Arizona. It's not a great time to be a state Republican.
Ignore the bad blood between Republican Gov. Jan Brewer and President Obama, who greet each other in public like old foes trying to borrow a cup of bile.
The FBI is conducting a massive investigation of state Attorney General Tom Horne, who with Brewer brought the immigration law case to the Supreme Court.
Horne is a popular Republican office holder who has had a little trouble in the past. In the course of a bankruptcy, Horne was slapped with a lifetime trading ban in 1970 by the U.S. Securities and Exchange Commission.
Now, the Arizona Capitol Times reports, the FBI investigation of Horne goes beyond claims by a whistle-blower -- a former friend and a current assistant -- Horne promised a job to Kathleen Winn, the woman who headed an independent committee that supported him.
The newspaper said the FBI was investigating Horne in January, a month before the former friend filed his whistle-blower complaint.
The FBI is investigating an allegation the Horne colluded with the "independent" committee during his 2010 campaign. That would be a violation of Arizona election law. The promise of a job would violate federal law, but a source told the Capitol Times the FBI and the Justice Department wouldn't be wasting their time on something as minor as that.
Though no one is saying publicly exactly what the FBI is looking at, agents recently have focused on corruption in other cases.
"What little we do know about the investigation so far is that the FBI has requested information on Horne's finances -- both for his campaign and in his personal life," the Capitol Times reports.
Another major Arizona law enforcement figure, Maricopa County Sheriff Joe Arpaio, is a target of the U.S. Justice Department's investigations.
Arpaio, a 79-year-old Italian-American transplant from Massachusetts bills himself as "America's toughest sheriff." He's famous for introducing tent cities, chain gangs and pink underwear to his overcrowded jail population.
The sheriff also has joined the "birther" movement -- the discredited attempt to prove that Obama wasn't born in the United States, and therefore is ineligible to serve as president, despite the presidential election.
Mainjustice.com reports the Justice Department has broken off negotiations with Arpaio to settle a case brought about by a three-year federal investigation. The department wrote sheriff's office lawyers that the Maricopa office refused to agree to an independent monitor, a necessary ingredient for any settlement of allegations of racial profiling of Hispanics, discriminatory jail practices and unlawful retaliation -- complain and you'll regret it.
Arpaio courts a reputation as a hard-liner on illegal immigration.
"It was disappointing, to say the least, for you to contact us 24 hours before our negotiations were scheduled to continue and raise, for the first time, a precondition that you understood would would result in the cancellation of negotiations -- and by extension, the initiation of a civil lawsuit -- and calls into question whether you were ever interested in settling this matter," Roy Austin, deputy attorney general in the civil rights division, wrote to Arpaio's department, mainjustice reports.
The precondition? The rejection of any monitor.
"I am [a] constitutionally and legitimately elected sheriff, and I absolutely refuse to surrender my responsibility to the federal government," Arpaio said in a statement. The sheriff said the Obama administration was trying to "strong arm me into submission only for its political gain," and "This will not happen; not on my watch."
Maricopa County Attorney Bill Montgomery told the Arizona Republic the state "is not the federal government's playground for you to come in here and throw around accusations and assertions and not back it up. If they provide this information, I'll take back everything I just said."
Back in Washington, in the larger fight over who gets to do what about illegal immigration, the finals briefs have arrived at the U.S. Supreme Court in preparation for the April 25 argument. They are important -- the justices usually refuse to hear arguments on which they haven't been briefed.
The Obama administration had challenged the state law, saying it usurped the role of the federal government. A federal judge agreed in part and issued an injunction against key parts of the law. A federal appeals court panel then decided the judge had the authority to issue the injunction.
The injunction bars enforcement of provisions of the law requiring police officers to question people about their immigration status during routine law enforcement operations, if officers have reason to suspect people are not in the United States legally.
The injunction also blocks a provision that criminalizes failure to apply for or carry alien registration papers, and a third that makes it illegal "for an unauthorized alien to solicit, apply for or perform work." Another blocked a provision that allowed police to arrest legal aliens thought to have committed a deportable act.
There is no question that Arizona has suffered from illegal immigration. Even U.S. District Judge Susan Bolton, who issued the injunction, conceded the state law was enacted against "a backdrop of rampant illegal immigration, escalating drug and human trafficking crimes and serious public safety concerns."
Arizona also says it has spent more than $760 million to jail illegal immigrants.
In its merit brief to the high court, Arizona says it "enacted the Support Our Law Enforcement and Safe Neighborhoods Act ... to address the illegal immigration crisis in the state"
Arizona argues in the brief that there is no usurpation of the federal role.
"This is an implied pre-emption case," the state says in its merit brief. "As such, there must be some clear conflict between a federal statute and [the state law]. The failure of federal law to authorize Arizona's efforts in express terms is beside the point. Arizona officials have inherent authority to enforce federal law and such cooperative law enforcement is the norm, not something that requires affirmative congressional authorization. [State law] does not impose its own substantive immigration standards, but simply uses state resources to enforce federal rules."
In its brief for the United States, the Obama administration said: "Arizona has adopted its own immigration policy, which focuses solely on maximum enforcement and pays no heed to the multifacted judgments that the [Immigration and Nationality Act] provides for the executive branch.
"For each state, and each locality, to set its own immigration policy in that fashion would subvert Congress' goal [in the act]: a single, national approach."
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