Marijuana businesses in the US and US investors in foreign marijuana businesses face a potpourri of federal tax issues. For example, the federal income tax treatment of a domestic marijuana business presents challenges for those entering the field. In 1982, Congress passed Internal Revenue Code (IRC) section 280E in response to a Tax Court case concerning a drug dealer who claimed ordinary and necessary business expenses related to his drug sales. Section 280E disallows deductions and credits for amounts paid…