Federalism.

Democrats hold a two-thirds majority of California legislature. We’ve already extended a big middle finger to the federal government on marijuana. Why not just ban the sale of firearms in the state, outright? 

And when someone sues and it goes to the federal courts and California loses, why not just do it again? Yell, “state sovereignty!” Yell, “states have the exclusive right to regulate public health and safety like Scalia says!” Then pass another law and do it again. Just keep enforcing the state law, no matter what the federal courts say.

California should just pick a fight with the federal constitution.