Judge John Mendez of the US District Court for the Eastern District of California [official website] on Wednesday blocked [order, PDF] the enforcement of provisions of California’s Immigrant Worker Protection Act [text] that would have fined employers who consent to immigration enforcement activities not mandated by federal law.

The act prohibits employers from providing consent to an immigration officer to “enter any nonpublic areas of a place of labor,” and from verifying employees’ immigration status except as required by federal law.

Judge Mendez, citing the Supremacy Clause of the United States Constitution [text], wrote that:

As in other intergovernmental immunity cases, the imposition of civil fines (like the imposition of taxes) turns on whether an employer chooses to work with federal immigration enforcement. These fines are a clear attempt to ‘meddl[e] with federal government activities indirectly by singling out for regulation those who deal with the government…’  The Court does not find Defendant’s argument that the law is neutral convincing.

The preliminary injunction only applies to private employers. Judge Mendez refrained from enjoining California’s ability to review immigration detention facilities within its borders.

This recent case comes after other federal rulings concerning immigration enforcement and sanctuary cities. In June a federal court ruled [JURIST report] that Philadelphia could maintain its status as a sanctuary city. And in March, a federal court upheld [JURIST report] a Texas law banning sanctuary cities.