“You have to use a nanny argument: The government needs to take control and regulate the market instead of leaving it to criminals,” she said. “The argument that you decide yourself what you put in your own body will never work in Norway.”

As a result, she added, “I would never use the word ‘legalize,’ but talk instead about regulating, not liberalizing.”

Ketil Lund, 75, the retired Supreme Court justice who advises EmmaSofia on its legal strategy, said he had never used psychedelic drugs and had no interest in trying them. But, he said, he supported Mr. Johansen’s campaign as part of a “bigger struggle” against antidrug policies in the West that he described as “an absolute failure.”

“The present narcotics policy in the West has so many detrimental effects,” he said. “These have to be balanced against detrimental effects of the drugs themselves.”

He said he was not qualified to adjudicate a raging debate over the possible hazards and benefits of psychedelic drugs like LSD. But he had been impressed by research suggesting that they were less harmful than alcohol. “People have used psychedelics for centuries,” he added.

The taboo in the West on psychedelics, however, is deeply entrenched — a legacy of government campaigns against drug use and a long backlash against the counterculture of the 1960s, when Timothy Leary, a Harvard professor and zealous promoter of LSD, urged Americans to “turn on, tune in and drop out.”

“LSD terrifies governments; it is their ultimate fear because it changes the way people look at the world,” said David Nutt, a professor of neuropsychopharmacology at Imperial College London. He was fired in 2009 as the British government’s drug policy adviser after he told a radio interviewer that alcohol was far more harmful than LSD and other psychedelics.