On Monday, January 1st, a new California law will go into effect designed to give undocumented immigrants some protections from federal immigration enforcement. The new law, called the Immigrant Worker Protection Act, includes the following new text:

(a) Except as otherwise required by federal law, an employer, or a person acting on behalf of the employer, shall not provide voluntary consent to an immigration enforcement agent to enter any nonpublic areas of a place of labor. This section does not apply if the immigration enforcement agent provides a judicial warrant. . . . (c) This section shall not preclude an employer or person acting on behalf of an employer from taking the immigration enforcement agent to a nonpublic area, where employees are not present, for the purpose of verifying whether the immigration enforcement agent has a judicial warrant, provided no consent to search nonpublic areas is given in the process.

Because "[t]he authority to control immigration . . . is vested solely in the Federal Government," Truax v. Raich, 239 U.S. 33, 42 (1915), California is ordering employers not to consent to federal immigration officers. Under the statute, an employer that voluntarily consents to a federal immigration inspection is subject to a civil fine. Another part of the same new statute enacts a new section of the labor code, Section 90.2, requiring California employers to notify employees ahead of time if federal immigration agents are coming to check employees' employment eligibility.

But wait, can a state interfere with federal immigration enforcement like that?

The short answer is, I don't know. This isn't my area, and I don't want to venture a guess with as little knowledge as I have. But my sense is that there's at least a serious question about it, and I thought I would say a bit about what I know and invite comments from those who know more.

Enforcement of immigraton law is up to Congress, not the states, and state law provisions that conflict with Congress's system of immigration enforcement are invalid under the Supremacy Clause. I gather the key case is Arizona v. United States, 567 U.S. 387 (2012), which considered whether federal immigration law preempted an Arizona state law designed to add extra state enforcement mechanisms. In Arizona, the Supreme Court held that state law provisions punishing failure to comply with federal alien-registration requirements, prohibiting unauthorized aliens to seek or engage in work in the State, and authorizing state arrests for federal offenses were preempted on the ground that they conflicted with the federal enforcement scheme and "create[d] an obstacle to the full purposes and objectives of Congress." Id. at 410. On the other hand, the Court declined to hold a state provision preempted that required state officers to make efforts to determine immigration status of stopped individuals absent a showing that "enforcement of the provision in fact conflicts with federal immigration law and its objectives." Id. at 416.

California's law seems sort of the mirror image of the Arizona law. While the Arizona law tried to add more enforcement of the immigration laws, California is trying to limit enforcment of the federal immigration laws. As I understand preemption doctrine, the key question is whether "the challenged state law stands as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress." Arizona, 567 U.S. at 399. Further, "[w]hat is a sufficient obstacle is a matter of judgment, to be informed by examining the federal statute as a whole and identifying its purpose and intended effects." Id. at 400.

I'm not sure how to apply these principles to the new California law. I'm a novice when it comes to preemption doctrine. The federal immigration laws are complex, and I'm wary of trying to work my way through them. So I'll leave the analysis to others with more background. To the extent it matters, though, there seems to be no clear statutory authority on point giving immigration officials inspection powers. The immigration agencies have various programs on inspections, see for example here, here and here. But my novice's sense is that these programs enforce the immigration laws without elaboring on the scope of powers given for that enforcement.

One interesting part of the picture is that the California law was expressly pitched as a means to undermine federal immigration policy. This is from the press release introducing the bill:

Amid escalating reports of the Trump Administration's indiscriminate raids on immigrants' homes and heart-wrenching stories of parents being snatched away from their children, Assemblymember David Chiu (D – San Francisco) was joined by workers from the Service Employees International Union (SEIU) California and the California Labor Federation to unveil legislation that represents California's latest and boldest challenge yet to Trump's hateful agenda against immigrants. AB 450 affirmatively protects workers from immigration enforcement through workplace raids, many of which unlawfully violate worker rights. For example, past raids occurred under the auspices of narrow individual arrest warrants that ICE used to question and detain every single worker at a worksite, including U.S. citizens and workers lawfully present—violating their basic constitutional rights. "Trump's threats of massive deportations are spreading fear among California workers, families, and employers," said Assemblymember Chiu, a son of immigrants and a former civil rights attorney. "AB 450 declares California's determination to protect our economy and the people who are working hard to contribute to our communities and raise their families in dignity. I'm proud to author this legislation which goes beyond California's existing defense of immigrants to offer new legal protections for individuals in our workplaces."

Can this "boldest challenge" to federal immigration policy withstand a preemption challenge? I'm guessing we'll find out, but in the meantime I hope others who know this area might offer more informed perspectives in the comment thread.