Earlier quoted context omitted.
and then the law would get struck down because, as said, washington state isn't allowed to regulate interstate commerce.
Nit to pick: States can and do regulate interstate commerce all the time. California once banned the import of foie gras into the state, and IIRC are planning a law banning the import of foreign oil. Some states ban the import of firearms they don't wish to exist. Whether they should be allowed to engage in the regulation of interstate commerce for activities that occur entirely extra-state is probably more along wha…
They can even regulate interstate commerce in ways that discriminate between in and out of state companies (IE something that seems a very clear commerce clause violation), though this is historically limited mostly to alcohol shipment :)
Honestly, though, the current SC seems much more likely to strike that all down than they have in the past, and give much brighter lines.