Federal legislation to allow physicians to prescribe marijuana legally is a long shot, supporters said Monday, though they contended that many lawmakers back it privately.

"I think support is strong, but people are still frightened a little bit by the politics of it," said Rep. Ron Paul (search), R-Texas. "If you had a secret vote in Congress, I'll bet 80 percent would vote for it."

Now that the Supreme Court (search) has ruled that California's state law doesn't protect people who use marijuana under a doctor's approval, the focus shifts to whether Congress will step in.

Click here to read the decision (FindLaw).

Don't bet on it, said Rep. Mark Souder (search), R-Ind., chairman of the House drug policy subcommittee.

"Denying the federal government the power to set and enforce uniform standards would simply open up an alternative route for illegal drug trafficking and abuse," Souder said.

Rep. Barney Frank (search), D-Mass., first sponsored the States Rights to Medical Marijuana Act in 1995. This year's version has just 30 co-sponsors, relatively few for a bill that is 10 years old.

Frank said many lawmakers don't mind letting the courts have the final say on this particularly thorny issue.

"They wish the courts would make the tough decision, and then they yell at the courts when they do," he said.

Frank said he didn't have high hopes that his bill would pass this year, either, but he said the court's ruling might help its prospects.

"They're not saying it's unconstitutional to pass a bill," he said. "What they're saying is that it's a congressional decision."

Nine states have laws similar to California's exempting from state criminal penalties those patients who use marijuana for medicinal purposes under a physician's supervision. Rep. Sam Farr, D-Calif., put a positive spin on what he said was a disappointing ruling.

"It gives it a national focus now," Farr said. "People in the states who have worked so hard to get their laws adopted will now focus their attention on Congress."

Frank's bill says that no provision of the Controlled Substances Act shall prohibit a physician from prescribing marijuana for medical use. Nor may it prohibit an individual from obtaining and using marijuana as prescribed. Also, the bill would allow pharmacies to obtain and hold marijuana in those states in which medical marijuana use is allowed.

The great majority of the co-sponsors of the States' Rights to Medical Marijuana Act are Democrats.

Paul, a physician who describes himself and his congressional district as conservative, is an exception. He said he approaches the issue from the perspective that the federal government should not be telling state and local governments what's best for them.

"The whole notion that the Supreme Court is going to allow the prosecution of people who raise a weed in their gardens that may be helpful to them is astounding," Paul said. "It's not very humanitarian as far as I'm concerned."

Souder disagreed, saying federal drug laws were designed to ensure uniform, scientifically based national health and safety standards for drugs and medicine.

"We cannot allow the state initiative process to undermine those standards on the basis of political, not scientific, arguments," he said.