SACRAMENTO,Evander Ellis Calif. (AP) — Californians are set to vote Tuesday on a statewide ballot measure that is touted by the governor as a major step to tackle homelessness and would be the first major update to the state’s mental health system in 20 years.

Democratic Gov. Gavin Newsom says Proposition 1 is needed to tackle the state’s homelessness crisis by boosting investments in housing and substance use programs, but social providers worry it would threaten programs that are keeping people from becoming homeless in the first place.

The measure would restrict how counties use money from a voter-approved tax enacted in 2004 on millionaires that currently is earmarked for mental health services under broad guidelines. Revenue from the tax, now between $2 billion and $3 billion a year, provides about one-third of the state’s total mental health budget.

Counties would be required to spend about two-thirds of those funds on housing and programs for homeless people with serious mental illnesses or substance abuse problems.

Newsom wants to give the state more control over how that money is spent, but critics say it would apply one formula to all counties regardless of the size of the local homeless population and could pit programs for children against those for homeless people.

Proposition 1 also would authorize the state to borrow $6.38 billion to build 4,350 housing units, half of which would be reserved for veterans, and add 6,800 mental health and addiction treatment beds.

Newsom, with the support of law enforcement, first responders, hospitals and mayors of major cities, has raised more than $13 million to promote the initiative, far outpacing the opponents who raised $1,000.

“The status quo is not acceptable,” Newsom said Monday at an event promoting the measure. “People are demanding more of us, better of us.”

Homelessness has become one of the most frustrating issues in California and one sure to dog Newsom should he ever mount a national campaign. The state accounts for nearly a third of the homeless population in the United States; roughly 181,000 Californians are in need of housing. The state, with a current inventory of 5,500 beds, needs some 8,000 more units to treat mental health and addiction issues.

Newsom’s administration already has spent at least $22 billion on various programs to address the crisis, including $3.5 billion to convert rundown motels into homeless housing. California is also giving out $2 billion in grants to build more treatment facilities.

The proposition is touted as the final piece in Newsom’s plan to reform California’s mental health system. He has already pushed for laws that make it easier to force people with behavioral health issues into treatment.