The controversial proposal, unveiled Tuesday, would pertain only to offenders charged with possessing small amounts of drugs, said Sen. Ken Gordon, the Denver Democrat putting forth the plan.

"I'm not trying to be soft on crime. I'm trying to be hard on crime," Gordon said. "I want to reduce the amount of crime in our society. People who have substance abuse problems don't just commit (drug crimes). They also commit forgeries, robberies, burglaries. They do things to get money for their drug abuse."

If approved, the move would free up space in Colorado's crowded prison system for violent offenders and save millions, supporters say. Democrats say it may be tough to sell Republicans on the idea, but criminal prosecutors said they might support it as long as treatment programs are mandatory and have a proven track record.

A meeting to hammer out the details with drug experts is planned later this month.

"I think DAs want to be fiscally responsible and if there's a creative way to treat drug offenders and free up funds to more effectively prosecute violent offenders, that merits consideration," said Peter Weir, president of the Colorado District Attorneys Council. "But we don't want to be diverting money under the rubric of treatment ... without a proven treatment program."

Even Republican Rep. Lynn Hefley, who chairs the Criminal Sentencing Committee, which will make the decision about whether to draft legislation, at first rejected the idea during a subcommittee meeting, then reversed course.

"It depends on what the district attorneys decide," Hefley said. "I think there are some valid points to treatment as long as it's on the front end, before someone goes to prison. But it will be difficult to convince people of this."

Seventy-five percent of the state's 16,764 prison inmates have substance abuse problems, according to the Department of Corrections.

Half are getting treatment at a cost of more than $4 million a year - about $318 per inmate, which the state wants to increase. The others are being turned out to the streets without treatment.

Gordon's proposal would funnel the savings for all drug offenders - not just those diverted from prison - to statewide treatment programs.

Of the 1,714 drug offenders serving time for drug possession, 52 are first-time offenders. Diverting just those from prison would save approximately $1.3 million a year for treatment, said Sen. Doug Linkhart, D-Denver, who favors the proposed legislation. Diverting all 1,714 would save the state more than $43 million a year, he said. It costs $26,000 a year to house one prisoner in a state prison. It is estimated it would cost far less to treat an offender, depending on the nature of the treatment, Gordon said.

While Colorado has little data on the effectiveness of drug treatment, one short-term study showed that the rate of recidivism dropped from 38 percent to 22 percent for prisoners who underwent treatment.

Nationally, many states are promoting treatment over prison and working to reform old drug laws.

The Western Governors Conference last year issued a white paper calling on member states, including Colorado, to find alternatives to incarceration and increase treatment for drug abusers. The paper noted that while drug-related spending by states was increasing sharply, drug use had remained unchanged since 1992. And though promising drug treatment programs were emerging, they were available to only a small fraction of those who needed it, the paper said.

New York's Gov. George Pataki recently proposed a plan that would give more defendants the opportunity to undergo drug treatment rather than serve long prison terms.

California and Arizona have passed laws requiring nonviolent drug offenders to enter rehabilitation rather than prison. While local prosecutors and even liberal legislators say California's law is too radical for Colorado, they are in the early stages of reforming the state's sentencing laws, starting with Tuesday's proposal.