Has Maines state law ever conflicted with federal law in such an obvious manner?
Yes. In 1850, Congress passed a law requiring free states to return escaped fugitive slaves to bondage in slave states. In 1855 and 1857, the Maine state legislature responded by enacting personal liberty laws that forbade Maine state officials from cooperating with the Fugitive Slave Act and also attempted to offer some degree of protection to Maine citizens who harbored fugitive slaves. As with marijuana today, the state could not impede the federal law, but the state could choose not to cooperate with a law its citizens saw as unjust. LD 1418 presents less of a conflict than the personal liberty laws because it merely creates an exception to Maine’s state law and does not attempt to impede federal action.