There is also the question of which branch of government gets to have a say in the enforcement of a law. Consider California's approach to marijuana use vs the Federal government's. Or consider how there are numerous sanctuary cities that are in defiance of Federal Immigration and Customs Enforcement.
These things are complicated.
After that it really depends upon how states respond and you could be stuck in a giant game of chicken. This is where it might get complicated and risky - mostly for people trying to abide by the law. Damned if you do, damned if you don't. But in this case, the government wont' really arrest you for not opening your car factory. But the state might arrest you for doing it.
In the case of Marijuana, it's really quite simple: everyone in California using marijuana can be arrested by the federal government. They just choose not to, at least usually.
ICE is a bit more complicated. They are trying to compel cooporation from local law enforcement, who is not responsible for enforcing immigration law. They aren't asking them to enforce it directly themselves though.