Connecticut last week became the 18th state to legalize recreational marijuana. Dozens of additional states allow various forms of medical marijuana use.

"If the Government is now content to allow States to act 'as laboratories' 'and try novel social and economic experiments,' … then it might no longer have authority to intrude on '[t]he States' core police powers … to define criminal law and to protect the health, safety, and welfare of their citizens," Thomas wrote. "A prohibition on intrastate use or cultivation of marijuana may no longer be necessary or proper to support the Federal Government's piecemeal approach."

In Standing Akimbo, the owners of a Colorado dispensary challenged the Internal Revenue Services' attempts to obtain their state business records and to deny them traditional business expense deductions. Internal Revenue Code 280E does not allow tax deductions for companies "trafficking" controlled substances.

The U.S. Court of Appeals for the 10th Circuit in April 2020 sided with the IRS, finding that the tax agency acted in good faith in seeking the dispensary's records to find out if the owners had taken improper tax deductions.

James Thorburn of the Thorburn Law Group, who represented the Standing Akimbo owners, called Thomas' statement "a stark rebuke of the federal government." Thorburn said in an email Monday that he believes the justices want more courts to weigh in on the state-federal marijuana conflict before they act "but we got some insight where they're leaning."

Thorburn also represented marijuana dispensary owners in a similar tax case, Speidell v. United States, that the Supreme Court denied without commentary last week.

The federal government's application of Internal Revenue Code 280E can siphon a large portion, if not all, of dispensaries' profits and remains a chief complaint of the state-legal industry.