Judge Blocks Parts of AZ Immigration Law

“Preserving the status quo through a preliminary injunction is less harmful than allowing state laws that are likely pre-empted by federal law to be enforced,” [Judge Susan Bolton of Federal District Court] said.

“There is a substantial likelihood that officers will wrongfully arrest legal resident aliens,” she wrote. “By enforcing this statute, Arizona would impose a ‘distinct, unusual and extraordinary’ burden on legal resident aliens that only the federal government has the authority to impose.”

Exactly. And it's already happened in Phoenix, even before the law existed.