WASHINGTON -- The Supreme Court questioned whether state medical marijuana laws might be abused by people who are not sick as it debated yesterday whether the federal government can prosecute patients who smoke the drug on doctors' orders.
Watching the argument was Angel Raich of Oakland, Calif., a mother of two who said she tried dozens of prescription medicines to ease the pain of a brain tumor and other illnesses before she turned to marijuana. She and another ill woman, Diane Monson, filed a lawsuit to protect their access to the drug after federal agents confiscated marijuana plants from Monson's yard.
Their lawyer, Randy Barnett of Boston, told the justices that his clients are law-abiding citizens who need marijuana to survive. It may have some negative side effects, he said, but seriously sick people are willing to take the chance because the drug helps them more than traditional medicines.
Three years ago the justices refused to protect the distributors of medical marijuana from federal charges. They are confronting a more personal issue this time: the power of federal agents to go after sick people who use homegrown cannabis with their doctors' permission and their states' approval.
The stakes are high because 11 states have passed medical marijuana laws since 1996. A defeat for the two California women might undermine those laws and discourage other states.
A loss for the government, on the other hand, could jeopardize federal oversight of illegal drugs and raise questions in other areas such as product safety and environmental activities. A Bush administration lawyer told the justices they would be encouraging people to use potentially harmful marijuana if they were to side with the women.
Justice David H. Souter said about 10 percent of people in America use illegal drugs, and states with medical marijuana laws might not be able to stop recreational users from taking advantage.
Despite the tenor of the debate, the case is difficult to predict. The justices are expected to rule before next summer.
The US Court of Appeals for the Ninth Circuit, in San Francisco, ruled that federal prosecution of medical marijuana users is unconstitutional if the drug is not sold, transported across state lines, or used for nonmedicinal purposes.
Justice Ruth Bader Ginsburg said the federal government has a stake in interstate commerce, but with the California medical marijuana patients, ''Nobody's buying anything. Nobody's selling anything."