It’s axiomatic that institutions, whether governmental, academic, philanthropic or corporate, rarely reform themselves.

Universally, if systemic change occurs, it tends to come from outside the existing structure for one overriding reason: Those who wield authority within the institution don’t want to risk having their powers diluted or eliminated.

California’s recent history offers several cogent examples of the syndrome, including the imposition of term limits on legislators and other state officials, the shift to a top-two primary election system and moving the decennial shuffling of legislative and congressional district boundaries from the Legislature to an independent commission.

That said, what’s happening in Los Angeles County could be an historic exception.

Three of the county’s five supervisors have voted, at least so far, to place a measure on the November ballot that would radically overhaul the county’s governance. They want to expand its Board of Supervisors from five members to nine and, even more dramatically, erode the board’s powers by creating an elected county executive — in effect, a county mayor.

Supervisors Lindsey Horvath and Janice Hahn first proposed the overhaul earlier this month and later gained support from Supervisor Hilda Solis. They acted despite opposition from the remaining two supervisors, Kathryn Barger and Holly Mitchell.

“We can no longer let a dated bureaucracy prevent us from more effectively addressing our homelessness crisis, making real progress on justice reform, or actualizing a government where Angelenos can meaningfully be at the decision-making table,” Horvath and Hahn said as they first aired their measure.

Mitchell and Barger didn’t oppose the overhaul directly, but complained that it was being rushed through without sufficient study.

“Something this significant and historic shouldn’t be entered with the comment ‘It’s not perfect,’” Barger said when the proposal was unveiled. “We have an obligation to our voters to make sure when we do this, we do it right.”

The board must take one more vote before the measure makes the ballot, but assuming it does, it will be ninth time that the huge county’s voters will consider expanding the board. Most recently, in 2000, 64% of voters rejected increasing the board to nine members.

Except for the combined city and county of San Francisco, California’s counties have long been governed by five elected supervisors, who wield both legislative and executive powers. It works reasonably well in smaller counties, including Alpine, for example, which has about 1,200 residents, but doesn’t in large urban counties such as Los Angeles, which has 10 million people — more than most states.

Each Los Angeles supervisor has about 2 million constituents, which means their campaigns collect and spend millions of dollars and only major interest groups can play the game. Board seats are so coveted that politicians will even give up seats in Congress in hopes of becoming one of the five.

Expanding the board would be a step towards making the board more reflective of the county’s immense diversity. But the second reform, having an elected county executive, is an even more fundamental change.

Having all authority vested in a five-member board makes decisive action more difficult than it should be and undercuts accountability. Voters don’t know who to blame when failures occur, or even who to credit when good things happen.

Given the size of the county, an elected county executive arguably would hold California’s second-most powerful office, eclipsed only by the governor, and it would be a natural stepping stone into the governorship.

Even if approved by voters, the systemic overhaul of Los Angeles County government would not take effect immediately. It would be phased in and become fully operational after the 2030 census.

Dan Walters is one of most decorated and widely syndicated columnists in California history, authoring a column four times a week that offers his view and analysis of the state’s political, economic,...