Marijuana was supposed to help Thailand. Why is the country planning to ban it again?

Two years ago, soon after Thailand became the first Asian nation to decriminalize cannabis, Sarunyu Toprasert and three friends joined a rush of pot entrepreneurs and launched the Channel Weed Store.

They opened their third location in early May, pouring $27,000 into the operation and bedecking the storefront with a neon light in the shape of a marijuana leaf and a poster advertising prices as low as $4 a gram.

Days later, the country’s prime minister announced that the government was reversing course and would ban recreational marijuana by the end of the year.

“It was a shock,” said Sarunyu, 33. “There were rumors of this happening before, but this time they sounded serious.”

As in California, legalization here hasn’t worked out as planned. Promises of economic salvation for poor farmers have not materialized. There are growing concerns that marijuana is harming children and making the already chaotic roads even more dangerous.

And a growing worry about methamphetamine — which remains illegal — has made drugs in general an appealing target for politicians. In parliamentary elections last year, most political parties campaigned against the recreational use of pot.

“Drugs are a problem that destroys the future of the country,” Prime Minister Srettha Thavisin said last month. “Many young people are addicted. We have to work fast.”