PHOENIX A federal judge blocked Arizona on Wednesday from enforcing a part of its immigration law that prohibits occupants of vehicles from stopping traffic to pick up day laborers.
In a preliminary injunction, U.S. District Judge Susan Bolton ruled that plaintiffs seeking to overturn the law were "likely to succeed on the merits of their claim" that the rules violate the First Amendment of the U.S. Constitution.
"Plaintiffs have also shown that they are likely to suffer irreparable harm in the absence of an injunction ... and that the public interest favors injunctive relief," Bolton said in the ruling.
Arizona's Republican Governor Jan Brewer signed the state's tough immigration law in April 2010, seeking to clamp down on illegal immigrants in the Mexico border state.
The law includes a requirement that police check the immigration status of anyone they have detained and suspected was in the country illegally. That provision was among measures blocked by Bolton before it came into effect in July 2010.
Arizona appealed the ruling to the U.S. Supreme Court, which will hear the case in April.
The section of the controversial law blocked on Wednesday sought to target people who employ migrant workers in the country illegally, many of whom gather in store parking lots and on curbsides in Phoenix to tout for work.
The non-profit National Day Laborer Organizing Network, which was a plaintiff in the suit, hailed the ruling.
"Today's decision is a victory for day laborers and everyone who cherishes the First Amendment right to free expression on public streets and sidewalks," the group's attorney, Jessica Karp, said in a statement.
Many Arizonans have supported the state's immigration crackdown, while President Barack Obama, many Democrats and civil rights groups oppose it.
Opponents of the law said it would lead to harassment of Hispanic-Americans. Obama has called such "piecemeal" state legislation a mistake and warned that having 50 different immigration laws around the country is untenable.
Brewer said in a statement she was disappointed by Wednesday's ruling, which she described as an "erroneous decision by the U.S. District Court to strike down a significant public safety component" of the law.
"The provision, which would have prohibited day laborers from blocking traffic when seeking work on public roadways, was put in place as a necessary traffic safety measure," Brewer said.
Arizona's appeal in the U.S. Supreme Court will be closely watched by Alabama, Georgia, Indiana, South Carolina and Utah, all of which have passed "omnibus" immigration crackdowns since Arizona did so.
(Reporting by Tim Gaynor; Editing by Cynthia Johnston and Paul Simao)