USCIS has issued new policy guidelines regarding federal controlled substance law, including violations involving marijuana, are generally a bar to establishing Good moral character (GMC) for naturalization.
This new law determines bans marijuana and other controlled substance users becoming US citizens through naturalization.
The policy guidance also clarifies that an applicant who is involved in certain marijuana-related activities may lack good moral character if found to have violated federal law, even if such activity has been decriminalized under applicable state laws.
Federal law classifies marijuana as a “Schedule I” controlled substance whose manufacture (which includes production, such as planting, cultivation, growing, or harvesting), distribution, dispensing, or possession may lead to immigration consequences.
Read the official announcement here