Three years ago, when Oregon voters approved a pioneering plan to decriminalize hard drugs, advocates looking to halt the jailing of drug users believed they were on the edge of a revolution that would soon sweep across the country.

But even as the state’s landmark law took effect in 2021, the scourge of fentanyl was taking hold. Overdoses soared as the state stumbled in its efforts to fund enhanced treatment programs. And while many other downtowns emerged from the dark days of the pandemic, Portland continued to struggle, with scenes of drugs and despair.

Lately, even some of the liberal politicians who had embraced a new approach to drugs have supported an end to the experiment. On Friday, a bill that will reimpose criminal penalties for possession of some drugs won final passage in the State Legislature and was headed next to Gov. Tina Kotek, who has expressed alarm about open drug use and helped broker a plan to ban such activity.

“It’s clear that we must do something to try and adjust what’s going on out in our communities,” State Senator Chris Gorsek, a Democrat who had supported decriminalization, said in an interview. Soon after, senators took the floor, with some sharing stories of how addictions and overdoses had impacted their own loved ones. They passed the measure by a 21-8 margin.

The abrupt rollback is a devastating turn for decriminalization proponents who say the large number of overdose deaths stems from a confluence of factors and failures largely unrelated to the law. They have warned against returning to a “war on drugs” strategy and have urged the Legislature to instead invest in affordable housing and drug treatment options.