Supporters of Proposition 36 pitched the tough-on-crime measure, which California voters overwhelmingly approved in November, as an urgent solution to compel people struggling with addiction into treatment and off the street.

In the four months since the measure took effect, however, no one charged with drug possession under the new law has been sent to an addiction program in either of the Bay Area’s two largest counties.

While it’s still too early to gauge Prop. 36’s ultimate impact, officials in Santa Clara and Alameda counties warn that a shortage of treatment options, coupled with the law’s “clunky and time-consuming legal processes,” are creating barriers to addressing voters’ growing frustrations over homelessness and public drug use.

“It’s a little disappointing that we haven’t gotten anyone in treatment, but the law is not really designed for streamlined treatment, so it hasn’t,” David Angel, an assistant district attorney in Santa Clara County, said at a public safety committee hearing last week.

So far, the county district attorney’s office — which raised similar concerns about Prop. 36 before its passage — has used the measure to bring at least 63 drug charges.

In Alameda County, meanwhile, the public defender’s office said it had received just one drug case charged under the law. The district attorney’s office there did not respond to questions about its charging decisions.

Prop. 36 empowers prosecutors to charge with a felony anyone caught with drugs or stealing property of any value more than twice, undoing part of a landmark 2014 crime reform measure that had reduced drug possession and lower-level theft to misdemeanors.

The new law also created a “treatment-mandated felony” that allows judges to order repeat drug offenders into treatment or sentence them to up to three years in jail or prison if they decline to enter a program. Courts have long offered such diversion deals, but the stiffer penalties are meant to push those into treatment who otherwise wouldn’t accept it.

District attorneys have broad discretion over whether to bring drug or theft charges under Prop. 36, meaning the law is playing out differently in counties across the state. In Orange County, for example, prosecutors have already filed around 1,200 treatment-mandated felonies. As of earlier this month, however, only 135 people had accepted treatment, and it was unclear how many had enrolled in programs.

Even as counties take different approaches to enforcing the law, there’s broad agreement that Prop. 36 is unlikely to succeed without more money to ensure treatment for those who agree to it. The measure provides no funding for addiction programs or the new court processes it mandates. And there’s concern it could slash existing dollars earmarked for treatment as the state spends more to imprison people.

In an interview, Alameda County Public Defender Brendon Woods contended the lack of funding reveals it was never Prop. 36’s intention to get people into treatment, especially since there already are too few options for drug users who actively want help.

“This measure was never, ever about treatment,” he said. “It was about incarceration.”

Although few people appear to be facing treatment-mandated felonies in drug cases in Alameda County, Woods said his office received 63 theft cases under the new law during its first three months. In Santa Clara County, the district attorney’s office said it has charged at least 51 theft cases using Prop. 36.

To address the funding challenges, Republican lawmakers have proposed setting aside between $250 million and $400 million a year to support Prop. 36. However, more of that money could go toward law enforcement and probation programs than to drug treatment. Democrats, meanwhile, have proposed a bill to track costs related to treatment-mandated felonies.

San Jose Mayor Matt Mahan, who campaigned for Prop. 36 last year, urged state and county officials to “move much faster” to add inpatient beds and transitional housing for those struggling with addiction. He cited Proposition 1, a $6.4 billion mental health bond the state is now in the process of disbursing to local governments. But state officials say that money must be used for opening new facilities and not ongoing treatment for those now being charged under Prop. 36.

Another roadblock, Santa Clara County prosecutors say, is what they describe as the complicated process for referring a Prop. 36 defendant to treatment. To enroll in a program, offenders must first go through multiple hearings and an in-depth assessment by an addiction expert, officials said.

The county behavioral health department, which is responsible for assessments and placing most people in treatment, said it’s phasing in the process gradually to ensure successful outcomes for program participants. As of last week, it had yet to receive a referral.

Sarah McCarthy, an assistant public defender in Santa Clara County, said many of her office’s Prop. 36 clients are wary of accepting treatment because, with so few options available, there’s no timeline for how long they may wait in custody even after they’ve been cleared for a program.

Defendants entering treatment must also first plead guilty to the felony charge, which is wiped away only after completing a program. McCarthy told county officials at last week’s public safety hearing that means if someone relapses — a common part of recovery — they could be stuck with the guilty plea and face a lengthy jail sentence.

She said some defendants may instead elect to fight the charge or seek a plea deal, a frequent outcome in criminal cases.

“Maybe there’s a credit-for-time-served, get-out-today offer on the table,” she said.