Although medical marijuana advocates never thought they would have the votes to bar federal prosecutions, some had predicted that because of the heightened interest after the Supreme Court's ruling that they would do better than Wednesday's 264-161 vote.

Rep. Barney Frank, D-Mass., said Tuesday that House Minority Leader Nancy Pelosi of San Francisco had been working the issue hard among Democrats and that he felt certain that there would be 180 or more votes for the amendment to a 2006 Justice Department funding bill.

Still, there was some comfort in Wednesday's vote for medical marijuana advocates. Since 2003, when the chamber took its first vote to bar spending money on federal prosecution of medical marijuana users, the number of members saying no to that idea has dropped by 11.

"We pick up votes each time as we continue to educate the public," said Steve Fox, communications director for the Marijuana Policy Project. "This is just a matter of time."

Among California's House members, 35 of the state's 53 representatives supported the amendment - roughly the same division as in earlier votes. Rep. Christopher Cox, R-Newport Beach, did not vote.

Sacramento-area congressional members reflect that stasis. The two new members since the last vote a year ago - Reps. Dan Lungren, R-Gold River, and Doris Matsui, D-Sacramento - voted like their predecessors.

"I am very concerned about drug use in this country and am opposed to efforts to legalize marijuana," said Matsui, elected in March to fill the seat of her late husband, Rep. Robert Matsui. "However, if in the course of treating an illness, a qualified physician feels that marijuana would offer a patient relief, then I think that patient should be allowed to purchase and use the drug with a prescription."

Lungren, who was state attorney general when California voters passed the medical marijuana initiative in 1996, voted against the one-year bar to federal prosecutions, calling it a "sledgehammer" treatment of an issue that needs considerable more study.

"Small amounts of marijuana for medical purposes have a way of turning into fairly large grows," Lungren said. "If this amendment passes, no matter how large the grow was, the federal government would be barred from eradicating it."

Lungren, like many other opponents Wednesday, said the focus should be on finding ways to synthesize marijuana's chemical compounds so they can be used safely in medical situations. But critics said that the federal government has stood in the way of such research.

Last week, the Supreme Court ruled 6-3 that state laws permitting marijuana possession and cultivation by patients with a doctor's recommendation are not a bar to federal enforcement of drug laws.

But in the majority opinion by Justice John Paul Stevens, the Supreme Court expressed sympathy for the sick for whom marijuana has been recommended by their doctors. The opinion urged a congressional review of the treatment of marijuana under federal drug laws.

Marijuana is now treated like heroin or other street drugs that are flatly illegal under any circumstances because they are not classified for medical use. Other drugs that may be addictive but that have a medical use are classified differently, and possession is not illegal if prescribed by a doctor.

In many ways, the debate over medical marijuana reflects a clash of cultures. Many advocates cite studies showing marijuana can be highly effective in treating the harshest symptoms of cancer, AIDS and other diseases, but opponents see the substance as a dangerous recreational drug and its medical uses a ruse for its eventual legalization.

Calling it a backdoor attempt to legalize marijuana, Rep. Mark Souder, R-Ind., said it was "shysters and quacks" who were prescribing it.

"This is a camel's nose under the tent" for legalization, said Rep. Steve King, R-Iowa.

But among the key sponsors of the amendment was Rep. Dana Rohrabacher, R-Huntington Beach.

Rohrabacher said that many drugs are harmful but still have medical benefits when taken under the guidance of a physician.

"Marijuana is no different than that," he said. "Let's not have a power grab by the federal government at the expense of these patients."

Pelosi called the vote "a state's rights issue" because it put the federal prosecution ahead of state laws that in eight instances, including in California, had been voter-approved.

"We must not make criminals out of seriously ill people," she said.

About the writer:

• The Bee's David Whitney can be reached at (202) 383-0004 or dwhitney@mcclatchydc.com.