At a hearing in Phoenix addressing an attempt by civil rights groups to stop the law before it goes into effect July 29, U.S. District Judge Susan Bolton said the U.S. Supreme Court has a long history of banning states from establishing immigration registration systems separate from the federal government, the Los Angeles Times reported.
Among other things, the law signed by Arizona Gov. Jan Brewer in April requires police to question people about their status if they've been detained for another reason and if police suspect they're in the United States illegally.
Critics said the law will promote racial profiling while bill supporters said the law is meant only to enforce federal law.
"What we're facing here is an attempt by a state to create an interrelated system of immigration laws that displace the federal" statutes, ACLU attorney Omar Jadwat said at the hearing Thursday, the Times reported.
Bolton will hear a separate challenge to the law by the Obama administration later Thursday.
In Washington Wednesday, the U.S. Senate rejected an attempt to bar federal funding for a legal challenge to the Arizona law.
Sen. Jim DeMint, R-S.C., and Sen. David Vitter, R-La., sponsored the move to attach the immigration measure to the extension of unemployment benefits, The Arizona Republic reported. Their amendment failed 55-43 in a partisan vote, with the Arizona Sens. John McCain and Jon Kyl, both Republicans, supporting it.
DeMint accused the Obama administration of trying to "intimidate" Arizona.
"This is something we know the American people -- if they could vote here today -- would vote in favor of," DeMint said. "The question is will the majority vote to support the people of Arizona or to support this political move that we're now seeing from the White House?"