PHOENIX — The U.S. Supreme Court has blocked Arizona from enforcing another provision of its controversial 2010 immigration law.

Without comment, the justices refused Monday to overturn a federal appellate court decision that concluded Arizona has no legal right to make it a state crime to knowingly transport or harbor illegal immigrants. The same provision also makes it illegal to “encourage or induce the alien to come to or live in Arizona.”

Monday’s ruling is the latest in a string of federal court decisions blocking Arizona from enforcing various sections of SB 1070.

The decision does not strike down the “harboring” provision in the law. It simply keeps in place an injunction issued two years ago by U.S. District Judge Susan Bolton staying enforcement while she considers arguments over its legality.

That process could take months or longer, as no date has been set for a trial.

But in issuing the injunction, Bolton had to conclude the challengers are ultimately likely to prevail in their arguments that the state exceeded its authority in enacting the law.

Gov. Jan Brewer, who signed the original 2010 measure and has fought to enforce it, was disappointed by Monday’s ruling, spokesman Andrew Wilder said.

“Arizona’s ability to combat criminal elements of illegal immigration in our own state is further eroded by this decision,” Wilder said. “The ruling is yet another blow to the state’s responsibility and authority to enforce public safety and defend the well-being of its citizens.”

But attorneys for challengers pointed out there already are federal laws making it a crime to harbor those here illegally.

The legal question for Bolton is whether Arizona can have its own statutes.

John Bouma, the private attorney hired by Brewer, has argued that there is nothing improper about Arizona having its own laws aimed at controlling immigration. And he said the fact that there are federal laws criminalizing the same conduct does not pre-empt state action.

But Omar Jadwat of the American Civil Liberties Union argued that the Arizona statute is not a mere parallel of the federal law.

He said the Arizona law creates “additional and different penalties not contemplated by federal law.” And Jadwat said that even where Arizona law overlaps federal harboring laws, it divests federal authorities of their “exclusive power to prosecute these crimes.”

Those arguments were enough to convince the 9th U.S. Circuit Court of Appeals, whose ruling the Supreme Court upheld.

Appellate Judge Richard Paez said allowing Arizona to have its own laws on harboring would effectively allow the state to bring charges against people in ways that actually would be contrary to federal policies, citing the Obama administration’s Deferred Action for Childhood Arrivals program allowing many of those who arrived here illegally as children to remain and work.

But Paez noted that Brewer has deemed those in the program “unlawfully present aliens.” He said that if Arizona were allowed to enforce its law, “it would authorize the prosecution of those who transport or provide shelter to these young people,” even though the federal government has said they can stay.