The Los Angeles County Board of Supervisors is poised to decide whether to undertake a massive expansion of the county’s sprawling jail system. The board should instead pause and rethink the misguided approach to fixing the inadequate treatment it provides inmates with mental illness.

There is no justification for spending up to $2.3 billion of taxpayer money on any plan that would do little to enhance public safety or improve the conditions that last year led the U.S. Department of Justice to condemn the treatment of mentally ill inmates and launch a probe of the jails.

This isn’t the first time the supervisors have rushed to fix the problems in the jails. Nearly 20 years ago, county officials signed off on another expensive plan to build the Twin Towers Correctional Facility. At that time, the facility was touted as a state-of-the-art jail that would ease overcrowding and improve conditions for mentally ill inmates.

Unfortunately, Twin Towers never lived up to that promise. It sat idle for a year and became a symbol of government incompetence.

In 1997, the Justice Department concluded that the county was failing mentally ill inmates, who were often going untreated and getting lost in the jail system.

Now the supervisors are once again scrambling to stave off any possible federal intervention. The reality is that a bigger and more expensive jail won’t help the vast majority of mentally ill inmates who all too often go without medication, or languish in their cells for days. And a bigger jail won’t prevent suicides or violence by deputies against the mentally ill in the jails. Those are deeply rooted problems in the county Sheriff’s Department and the Department of Mental Health.

A far more sensible approach would be for the supervisors to wait for a new sheriff to be elected. Every candidate for sheriff has stated that he wants to significantly reduce the number of inmates with mental illness and put them in more appropriate community care, as well as to consider diverting low-level offenders out of the criminal justice system and into local treatment programs that offer far better public safety outcomes and are far cheaper.

But the proposal in front of the board would not allow a new sheriff the chance to implement his vision. Instead, the new sheriff would be tied to a plan that ignores the real problems that plague the jails.

It is little wonder the candidates support diversion programs. They understand that diversion program have helped other cities reduce crime and government spending on incarceration.

Consider, for example, that a diversion program in Florida’s Miami-Dade County has led to a drastic reduction in the recidivism rates among people who committed misdemeanors and nonviolent felonies, such as drug possession. Other cities with diversion program report similar results.

The supervisors are right to attempt to address the longstanding problems in the jails and improve the treatment of mentally ill inmates. And they may need to shutter Men’s Central Jail and replace it with a more modest facility.

But the supervisors would be foolish to think they can simply build their way out of the current crisis with a massive and expensive new treatment jail.

Cross-posted from the Los Angeles Daily NewsHector Villagra is executive director of the American Civil Liberties Union of Southern California. @HectorSoCalACLU