"While we understand the frustration of Arizonans with the broken immigration system, a patchwork of state and local policies would seriously disrupt federal immigration enforcement and would ultimately be counterproductive," DOJ spokeswoman Hannah August said in support of Wednesday's ruling.
"It's a preliminary injunction so it's not final," said attorney Linton Joaquin with the National Immigration Law Center, which is party to one of the lawsuits challenging the law. "But the judge showed the most egregious provisions are pre-empted by federal law."
"It's good news for everybody," said Ali Noorani of the National Immigration Forum. "For now, all residents of Arizona will remain protected under the law."
Supporters of the law were disappointed at Wednesday's ruling but pointed out that the blocked provisions could still take effect after the court resolves legal questions surrounding them.
"Today the Federal Government got relief from the courts to not do their job," said Gov. Brewer. "We knew regardless of what happened today of course one side or the other side was going to appeal. So this begins the process. This is an injunction. They haven't heard really the merits of the bill."
Steven Camarota of the Center for Immigration Studies, which favors the Arizona law, said Wednesday's decision was not unexpected. "The law had a lot of safeguards built into, but ultimately the judge didn't believe that Arizona could implement the law in an unproblematic way. This is strange because it assumes that, but there hadn't been any cases of misuse of the law."
Arizona Senators John McCain and Jon Kyl also expressed disagreement with the court's opinion and called the federal lawsuit against Arizona a "waste of taxpayer resources."
"The Obama Administration should have focused its efforts on working with Congress to provide the necessary resources to support the state in its efforts to act where the Federal government has failed to take responsibility," they said in a statement.
Judge Bolton did not rule Wednesday on various requests by lawyers for Arizona and Gov. Brewer to dismiss the various lawsuits against SB 1070. She also still has to decide on other preliminary requests to block parts of the law.
"After a preliminary injunction there is a trial on the permanent injunction," said New York Law School professor Lenni Benson.
The judge "can dissolve it later if, after greater consideration or development of more facts and time to assess the law, the judge thinks the law goes the other way."
The legal process is expected to drag on for months, after which, legal experts say, parties may still appeal parts of the decision they don't like. The debate over SB 1070 could reach the U.S. Supreme Court.
"This is a significant decision, and the litigation, as it proceeds to a final decision...and probable appeal, has potentially historic dimensions," said Hiroshi Motomura of the UCLA School of Law.