The House of Representatives on Wednesday refused to allow cancer patients and other severely ill people to smoke marijuana to ease pain, as opponents argued the measure was a back-door attempt to legalize the substance.

By a vote of 264-161, the House rejected a measure that would have stopped federal law enforcement authorities from prosecuting medical marijuana users in 10 states that allow it when prescribed by doctors.

This marked the third time since 2003 that the House has defeated the initiative. This year, supporters picked up 13 votes.

Proponents of the controversial legislation hope to build Republican support and could try for another House vote next year. Only 15 Republicans out of 231, supported the measure.

“While we’re disappointed that the amendment did not pass, a record 161 House members voted today to stop arresting medical marijuana patients,” said Rob Kampia, executive director of the Marijuana Policy Project in Washington.

The House debate came about one week after the U.S. Supreme Court ruled that the federal government - not the states - had the power to regulate drug use.

Rep. Mark Souder, an Indiana Republican who worked to defeat the marijuana initiative, accused supporters of “hiding behind a few sick people to try to in effect legalize ... marijuana in this country.”

“The rhetoric about marijuana as a treatment for medical purposes was probably dreamed up at some college dorm,” he said.

Rep. Maurice Hinchey, a New York Democrat, countered that the measure would not encourage the recreational use of marijuana or legalize it nationwide. “It would give relief to people suffering from horrific diseases and allow their doctors to decide which drugs will work best,” Hinchey said.

Supporters were trying to attach the measure to a $57.5 billion bill to fund several federal agencies next year, including the Department of Justice.

Smoking marijuana can ease nausea caused by cancer treatments and can stimulate appetite in patients too sick to eat. Religious groups and some medical organizations have supported its use for patients suffering from cancer, AIDS, Glaucoma and other severe illnesses.

Rep. Dana Rohrabacher, a conservative California Republican, called on the House to respect state laws, including California’s, which allow medical marijuana.

“Let’s not have a power grab by the federal government at the expense of these poor patients and the right of doctors to make these decisions and not politicians,” Rohrabacher said.

Alaska, California, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Vermont and Washington have similar laws allowing the use of medical marijuana.

On Tuesday, the Bush administration urged the House to defeat the marijuana measure, saying Congress should not “circumvent the recent Supreme Court decision.” It added that “states should not have the authority to independently designate a substance that has not been recognized by the Food and Drug Administration as an approved medicine.”

Souder said smoking marijuana is unnecessary now that a federally-approved prescription drug, Marinol, is available to treat nausea and vomiting associated with cancer chemotherapy.

But Angel Raich, a Californian with an inoperable brain tumor and other medical problems who brought the marijuana case to the Supreme Court, on Monday said she has severe reactions to prescription drugs. “I need cannabis every two hours to survive,” she said.

Rep. Lynn Woolsey, a California Democrat who supported the amendment, told House colleagues that her now deceased mother used marijuana to treat glaucoma.