A federal judge has barred use of a policy that allowed people who paid to be sneaked into the United States to be charged under Arizona's immigrant smuggling law as conspirators to the crime.

U.S. District Judge Robert Broomfield's ruling Friday said the interpretation of the 2005 state law conflicts with federal law.

Broomfield's ruling is the latest in a series of restrictions placed on Maricopa County Sheriff Joe Arpaio's immigration enforcement efforts.

Seventy-five percent of the people charged under the smuggling law in the state's most populous county through June 2011 were charged with conspiring to sneak themselves into the country.

Immigrant rights advocates argued that the law was intended for often-violent smugglers, not their customers.

Defenders of the tactic argued that the interpretation didn't conflict with federal law.