Final answer:
It is generally illegal to serve alcohol to a person who is visibly intoxicated, regardless of whether their intoxication comes from alcohol or another substance, due to laws aiming to prevent harm.
Step-by-step explanation:
The question relates to the legalities surrounding the service of alcoholic beverages to an individual who is visibly intoxicated, whether from alcohol or another substance. According to the laws of many states, serving alcohol to a visibly intoxicated person is illegal. These laws are in place to prevent harm not only to the intoxicated individual but also to others. The laws may vary by state, but the general principle is rooted in preventing further intoxication and any potential consequences that might arise from it, such as accidents or health risks. Therefore, even if the intoxication stems from a substance other than alcohol, a bartender or server could potentially face legal issues for contributing to that individual's intoxication by providing them with more alcohol.