> CA has stricter environmental regulations. Numerous states have stricter minimum wage laws. Labor laws. Etc. A lot depends on how the federal law is written.

> CA has stricter environmental regulations. Numerous states have stricter minimum wage laws. Labor laws. Etc. A lot depends on how the federal law is written. Federal law can be written to completely preempt state law in some given area or it can be written to only preempt state law in the specific things in that area that the federal law actually provides rules on. For wages federal law sets a minimum wage but does not prohibit states from setting their own higher minimum wage. For many environmental laws federal law is written to completely preempt state law. States in those areas cannot set stricter standards. For some of those, such as car emissions, the federal law completely preempts (which would stop California from having stricter regulations) but the EPA is authorized to issue waivers to allow states to be more strict. There is such a waiver for California that allows them to set their own stricter standards and allows other states to choose to follow the California standard. The Trump administration revoked California's waiver. (And then when several car companies announced they were going to continue to meet California's standard even if no longer required to do so the Trump administration threatened to sue them for antitrust). The Biden administration restore California's waiver.