Supreme Court Justice Clarence Thomas called into questioned federal marijuana prohibition, saying the fed’s inconsistent laws and enforcement have undermined the government’s case for keeping weed illegal.

“A prohibition on interstate use or cultivation of marijuana may no longer be necessary or proper to support the federal government’s piecemeal approach,” Thomas, one of the court’s most conservative justices, wrote in a statement.

The court’s decision not to hear a new case related to tax deductions claimed by a Colorado medical marijuana dispensary prompted Thomas to issue a statement that more broadly addressed federal marijuana laws.

Thomas stated that a 2005 ruling in Gonzales v. Raich in particular, which determined that the federal government could enforce prohibition against marijuana possession, may be outdated.

“Federal policies of the past 16 years have greatly undermined its reasoning,” Thomas added. “The federal government’s current approach is a half-in, half-out regime that simultaneously tolerates and forbids local use of marijuana.”

Thomas also noted how prohibition threatens federalism:

“If the Government is now content to allow States to act ‘as laboratories, 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 said.

In the 2005 Raich case, in which the Supreme Court upheld federal prohibition, Thomas said :

Respondents Diane Monson and Angel Raich use marijuana that has never been bought or sold, that has never crossed state lines, and that has had no demonstrable effect on the national market for marijuana. If Congress can regulate this under the Commerce Clause, then it can regulate virtually anything–and the Federal Government is no longer one of limited and enumerated powers.

“Our federalist system, properly understood,” Thomas wrote, “allows California and a growing number of other States to decide for themselves how to safeguard the health and welfare of their citizens.”

There’s at least one consistent, strong voice for ending marijuana prohibition on the Supreme Court. And it’s arguably that of the court’s most conservative member. The right would be wise to take Mr. Justice Thomas’ enduring concerns about liberty and limited government to heart.