On November 19, 1992, California Attorney General Dan Lungren issued a legal opinion.
In brief, it said:
Question
"May a city prohibit its officers and employees from cooperating in their official capacities with Immigration and Naturalization Service investigation, detention, or arrest procedures relating to alleged violations of the civil provisions of the federal immigration laws?"
Conclusion
"Due to the supremacy clause of the United States Constitution, a city may not prohibit it officers and employees from cooperating in their official capacities with Immigration and Naturalization Service investigation, detention, or arrest procedures relating to alleged violations of the civil provisions of the federal immigration laws
