Smokeless in Seattle

IT was January of 1998 when a friend and I drove to a basement in South Seattle to set up a pot garden. We were terrified. If a police officer pulled us over, how would we explain these bags of rapid-bloom fertilizer — in winter?

Still, we had to go. A friend was suffering from the late stages of a degenerative muscular disease. He spent all day strapped into something that looked like a hospital bed crossed with an easel. Smoking pot helped ease his pain; after his wife held joints to his lips, he would eat soup. He would watch TV. He’d laugh.

Growing pot was illegal at the time, but stories like ours, and a strong public campaign, persuaded 59 percent of Washington State voters to legalize medical marijuana that fall. In the 14 years since, an entire industry has emerged to serve incapacitated patients like my friend, who couldn’t grow pot himself. Doctors write authorizations, dispensaries sell the stuff, trade magazines flourish.

In the eyes of most opponents and many supporters of easing pot laws, medical marijuana is supposed to be a slippery slope to full legalization. But in Washington, the opposite is happening: a momentous initiative to legalize marijuana for all adults, which will be on the ballot this fall, is being opposed by the medical marijuana industry that the previous initiative created.

Initiative 502, as the measure is known, would allow adults 21 and older to possess up to an ounce of marijuana without penalty. The state would issue licenses to marijuana farmers, distributors and even stores, which could then sell pot over the counter like beer.

The plan, supported by the likes of John McKay, a former federal attorney, and Rick Steves, the travel writer, is about more than stoners’ rights: legalizing and regulating the pot market would wrest profits from murderous foreign cartels while helping the beleaguered state budget. Officials recently estimated the measure could generate up to $606 million in tax revenue in the first year.

Every recent poll except one has shown most Washington voters are now ready to pass the initiative. But support has slipped since last fall, down to only 51 percent, according to SurveyUSA. The flagging enthusiasm correlates with the escalating effort to stop the initiative.

In late February, Dr. Gil Mobley, a physician with a local clinic providing medical-marijuana authorizations, began a campaign called No on I-502, a new name for a group that, before, called itself Patients Against I-502. It anticipates donations from lawyers and doctors, said its treasurer, Anthony Martinelli, and pot dispensaries may also finance a fall volley of television commercials.

The campaign claims that a provision in Initiative 502 would penalize medical marijuana users who drive with active THC, the psychoactive compound in marijuana, in their blood, even a day or a week after the last time they got high. (Any driver who exceeds a limit of five nanograms of THC per milliliter of blood would be automatically guilty of driving under the influence.) They also complain that the law would have zero tolerance for drivers under 21 years old with active THC in their blood. Mr. Martinelli goes so far as to claim that the measure “will take away driving for all cannabis users.”

The anti-502 effort has also played on civil liberties fears. A glossy medical-marijuana magazine, Dope, warned recently that patients would be required to apply for licenses if they wanted to grow cannabis and that the Drug Enforcement Administration could then access their names.

This type of opposition isn’t uncharted political territory: In 2010, a group of medical marijuana dispensaries banded together to help narrowly defeat a legalization initiative in California.

What’s the threat? A legal, regulated market for all consumers — not just sick people — could negate demand for a niche medical pot industry altogether.

“The medical marijuana industry is driven by profit,” said Allen St. Pierre, executive director of the National Organization for the Reform of Marijuana Laws, which supports medical marijuana legalization. “It’s not driven by compassion anymore. It is driven by the need to make money.”

What’s more, the opposition doesn’t even have a compelling case. I haven’t found a single scientific study showing that even the heaviest of pot users would exceed the five-nanogram cutoff after 24 hours. And the civil liberties attacks are simply dishonest. The rules would remain the same as they currently are for medical marijuana — no registration requirements and no database.

For their part, I-502’s critics insist that they have no financial motivation and that they support legalization, just not this initiative and its D.U.I. regulations. But it’s more than a little strange to defend the status quo, in which nearly 10,000 people are arrested in Washington for possession each year, on civil liberties grounds. And it’s not as if voters would accept a law that didn’t include restrictions on smoking and driving.

Washington State has a chance this fall to siphon profits from cartels while stopping senseless arrests, or it can let the status quo prevail. It’s a simple choice, particularly given that concerns from the medical marijuana industry are, at best, red herrings.