The general rule is that when a federal and state laws conflict, federal law wins. This almost always happens under the Supremacy Clause of the Constitution. But election law issues arise under the Elections Clause of the Constitution, which says that states have primary responsibility for conducting elections but that “Congress may at any time by Law make or alter such [state] Regulations.”
The Supreme Court has previously held that the Elections Clause sets a higher bar for states than the Supremacy Clause. To respect state sovereignty, courts presume a state law is not preempted by federal law under the Supremacy Clause unless Congress makes explicitly clear that it wants to trump the states. If that were the rule in Gonzalez, then Arizona’s law would win on both issues in this case.
But the Supreme Court has not to date applied that same rule to election laws. Instead, it has said that federal election law automatically displaces state election laws. So even though there is a way to make Arizona’s statute coexist alongside NVRA, the Ninth Circuit held that Arizona’s citizenship-proof requirement must go.
Chief Judge Alex Kozinski joined the majority, but also wrote a separate concurring opinion. In it Kozinksi observed that, “the Supreme Court has never articulated any doctrine of giving deference to the states under the Elections Clause… A case such as ours, where the statutory language is unclear and the state has a compelling interest in avoiding fraudulent voting by large numbers of unqualified electors, presents a far more suitable case for decide whether we should defer to state interests. But only the Supreme Court can adopt such a doctrine.”
So the messy split here, with some judges voting to strike down one provision, others voting to uphold both, and others voting to strike down both, might make this a tempting case for the Supreme Court to take. The fact that Kozinski—a libertarian appointed by Ronald Reagan and one of the most brilliant judges on the entire federal bench—wrote that only the Supreme Court can reorient the Elections Clause, and that it should do so here, increases the odds that the justices will take the case.
In the end, this was an important win for voter-ID laws. And if the justices take this case it could become a broad-based win that would strengthen state sovereignty and diminish centralized federal control of the democratic process on Election Day. That would be a welcome development.