A trademark must be in lawful use in interstate commerce for the U.S. Patent and Trademark Office ("USPTO") to register it. See TMEP 907. If a trademark or the goods/services offered in conjunction with a trademark violate federal law, the USPTO will refuse registration under Sections 1 and 45 of the Trademark Act because the mark is not in lawful use. 15 USC 1051, 1127.
The federal Controlled Substances Act, among other things, prohibits the manufacturing, distributing, dispensing, or possessing of marijuana and marijuana-based preparations. Therefore, the USPTO will (and frequently does) refuse the registration of trademarks for marijuana or goods containing marijuana. Further, the USPTO is a federal office governed by federal law, so the fact that marijuana may be legal in the applicant's state is irrelevant.
Therefore, if MARIJUISKEY is a whiskey that contains marijuana, the applicant will get a refusal under Sections 1 and 45 of the Trademark Act, though that refusal may be premature at this point. This application was filed on an intent-to-use basis, meaning the applicant has not yet submitted a specimen showing the USPTO how it uses this mark on its goods (and a cursory review of the applicant's website does not reveal this whiskey). Therefore, other than assumptions about the name, there's currently nothing to suggest this whiskey has anything to do with marijuana.
However, the mark itself may prompt the examining attorney assigned to this application to issue an inquiry into the lawfulness of the applicant's goods and request additional information, which they are permitted to do. See TMEP 907. If the applicant's evidence indicates this whiskey does contain marijuana, and therefore isn't lawful at the federal level, the USPTO may refuse registration based on this "extrinsic evidence" even if the description of goods in the application itself (i.e., "distilled spirits, namely, whiskey") is lawful. Id. On the other hand, if it turns out MARIJUISKEY whiskey doesn't contain marijuana, there's no basis for a refusal based on unlawful use.
Interested in the fate of MARIJUISKEY? Check in on the application in approximately three months after it is reviewed by an examining attorney.