The US Supreme Court on Monday upheld the power of Congress to prohibit and prosecute the possession and use of marijuana for medical purposes, even in the 11 states that permit it.
The 6-3 decision, a firm reassertion of federal authority, revealed a deep fissure within the coalition that over the past decade has provided the majority for a series of decisions curbing congressional power and elevating the role of the states within the federal system.
Two members of that coalition, justices Anthony Kennedy and Antonin Scalia, voted this time to uphold federal authority.
The decision overturned a 2003 ruling by a federal appeals court that had shielded California's Compassionate Use Act, the medical-marijuana initiative adopted by the state's voters nine years ago, from the reach of federal drug enforcement.
The appeals court had held that Congress lacked constitutional authority to regulate the noncommercial cultivation and use of marijuana that does not cross state lines.
But "the regulation is squarely within Congress' commerce power," Justice John Paul Stevens said for the majority on Monday.
Under the terms of the opinion, the 9th US Circuit Court of Appeals in San Francisco will now consider other challenges to the application of federal drug law, including an argument made by the two patients who brought the case that depriving them of what they say is the only drug that eases their suffering from a variety of painful conditions amounts to a violation of their constitutional right to due process.
Because the two women, Angel McClary Raich and Diane Monson, prevailed in the 9th Circuit on their Commerce Clause argument, the appeals court did not address the other issues they raised.
In addition, Stevens, noting that "perhaps even more important than these legal avenues is the democratic process," suggested that the executive branch might reclassify marijuana for medical purposes or that Con-gress might take up the matter.
Advocates for medical marijuana, meanwhile, emphasized on Monday that the state laws remained in effect and that the prospect of federal enforcement was fairly remote.
The opinion by Stevens was joined by his allies in many recent battles over federalism, justices David Souter, Ruth Bader Ginsburg and Stephen Breyer, and by Kennedy.
Meanwhile, the House of Representatives is due to vote next week on an appropriations amendment that would prohibit the Justice Department from spending money to enforce federal drug laws against patients using marijuana for medical purposes. While the amendment failed last year, 19 Republicans voted for it.