The marijuana users won in the San Francisco-based 9th U.S. Circuit Court of Appeals, which ruled that federal prosecution of medical marijuana users is unconstitutional if the pot 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."

Her colleague, Justice Sandra Day O'Connor, observed that homegrown medical marijuana never makes it to the interstate market.

Conservatives like Chief Justice William H. Rehnquist, Justice Clarence Thomas and Scalia generally have supported states' rights to set their own policies.

Rehnquist, who is undergoing treatment for thyroid cancer, missed Monday's argument and is not expected to return to the court until January, at the earliest.

Raich said she hopes the 80-year-old chief justice's chemotherapy treatments "would soften his heart about the issue."

"I think he would find that cannabis would help him a lot," said Raich, who uses marijuana every few hours for scoliosis, a brain tumor, chronic nausea and other illnesses.

California's law allows people to grow, smoke or obtain marijuana for medical needs with a doctor's recommendation. Besides California, other states with such laws are: Alaska, Arizona, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Vermont and Washington.

Medical marijuana was an issue in the November elections. Montana voters easily approved a law that shields patients, their doctors and caregivers from arrest and prosecution for medical marijuana. Oregon rejected a measure that would have expanded its medical marijuana program dramatically.

The case is Ashcroft v. Raich, case no. 03-1454.

Attorneys for White House, women press their cases

WASHINGTON (AP) -- The Supreme Court questioned whether state medical marijuana laws might be abused by people who aren't really sick as it debated on Monday whether the federal government can prosecute patients who smoke pot on doctors' orders.

Watching the argument was Angel Raich, an Oakland, California, 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 attorney, Randy Barnett of Boston, told the justices that his clients are law-abiding citizens who need marijuana to survive. Marijuana 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.

The justices refused three years ago to protect 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 from approving their own.

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.

"Smoked marijuana really doesn't have any future in medicine," said Paul Clement, acting solicitor general.

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.

"Everybody will say mine is medical," Justice Stephen Breyer said.

And Justice Antonin Scalia said there are many people with "alleged medical needs."

Despite the tenor of the debate, the case is hard to predict. The justices will rule before next summer.