To those with family members who rely on medical marijuana to relieve chronic pain, the federal government's crusade against the use of the drug is an outrage. According to a 2005 Gallup poll, 78 percent of Americans support allowing doctors to prescribe medical marijuana. Yet only one of the three major presidential candidates, Sen. Barack Obama, is calling for needed change in federal policy by stopping federal raids in the 12 states that have passed laws legalizing medicinal use of marijuana.

In my 20s, I had expected my generation to understand the futility of Big Government drug laws. Au contraire -- now in power, my generation imposes prohibitions on people who are seriously ill and in pain. Bill Clinton's administration went after doctors who recommended marijuana. Under George W. Bush, federal authorities have raided medical marijuana suppliers.

As The Chronicle's Bob Egelko reported Monday, Sen. Hillary Rodham Clinton has spoken out against Drug Enforcement Administration raids on medical marijuana clubs. But last month in an interview with the Willamette Week in Oregon, Clinton would not say whether she would stop the raids, only that medical-marijuana raids "would not be a high priority."

Sen. John McCain opposes medical marijuana use. But on the campaign trail last year, he said that medical marijuana was an issue for states to decide and he pledged to do "everything in my power" to keep a seriously ill patient who used medicinal marijuana from being arrested.

"I gotta say, I'm not sure what happened to the Straight Talk Express on this one," quipped Marijuana Policy Project spokesman Bruce Mirken.

As a self-styled straight-talking maverick, McCain should rethink his position on medical marijuana use. Of course, he is free to personally oppose it, but as a conservative, he should support the right of states to buck a heavy-handed federal mandate. As a human being, he should respect the right of sick people, and their doctors, to avail themselves of a drug that relieves nausea, pain and discomfort and stimulates the appetite of cancer patients on chemotherapy.

McCain spokesperson Crystal Benton cited the American Medical Association's recommendation that marijuana remain a Schedule I drug -- with "no accepted medical use" under the Controlled Substances Act -- until and unless studies, heretofore essentially barred by Washington politicians, establish medical uses. Be it noted, the AMA, like other medical groups, advocates more research on marijuana's potential treatments.

The American College of Physicians also wants more research. In the meantime, the group has called for reclassification of marijuana, "given the scientific evidence regarding marijuana's safety and efficacy in some clinical conditions." That is, let doctors and patients -- not government -- decide what works for them.

Obama's position is not as clear as some advocates might prefer. Spokesman Ben LaBolt noted that Obama supports having the Food and Drug Administration regulate marijuana for medical use -- a bad idea and a surefire way to bureaucratize and corporatize what has been a grassroots enterprise.

What about real and dangerous abuses, such as dealers who are running criminal enterprises disguised as cannabis dispensaries? LaBolt answered that Obama "believes that states and local governments are best positioned to strike the balance between making sure that these policies are not abused for recreational drug use and making sure that doctors and their patients can safely access pain relief."

As for McCain, he would do well to heed the words of economist and conservative icon Milton Friedman, who before his death told Forbes, "There is no logical basis for the prohibition of marijuana." And: "It's absolutely disgraceful to think of picking up a 22-year-old for smoking pot. More disgraceful is the denial of marijuana for medical purposes."