Sophia Bollag, Associated Press

UPDATED 4:17 p.m.

(AP) — A measure that would divide California into three parts won't appear on the November ballot, the state Supreme Court decided Wednesday, marking the latest defeat for a long-shot push to reimagine the nation's most populous state.

The justices ordered the secretary of state not to put the ballot initiative before voters, saying significant questions have been raised about its validity. The court now will consider a challenge from the Planning and Conservation League, an environmental group that argued splitting up California would drastically change its government structure beyond what can be accomplished through a simple ballot initiative.

"We conclude that the potential harm in permitting the measure to remain on the ballot outweighs the potential harm in delaying the proposition to a future election," the justices wrote in a unanimous ruling.

They said time constraints forced them to rule on the issue immediately. If the court ultimately rules in favor of the initiative, it could go before voters in 2020.

Venture capitalist Tim Draper, who has spent more than $1.7 million supporting the initiative, has tried for years to split the state, arguing it has become ungovernable because of its size, wealth disparities and geographic diversity. His last attempt to divide California in six didn't gather enough signatures to make the ballot in 2016.

Draper criticized the ruling, saying ballot initiatives are intended to ensure that the government represents the will of the people. He argued the court's decision subverts the process.

The environmental group argued the measure exceeded the scope of what could be passed through a simple initiative. The director of the Planning and Conservation League says it would have created chaos and not solved any of the state's problems.

The director of the Planning and Conservation League cheered the decision.

The initiative "was a costly, flawed scheme that will waste billions of California taxpayer dollars, create chaos in public services including safeguarding our environment," Howard Penn said in a statement. "It would have dismantled the world's fifth biggest economy without solving a single challenge facing Californians today."

The environmental group's lawsuit says major changes to the state's government structure require approval from two-thirds of the Legislature before being considered by voters or a state constitutional convention.

Draper has argued that the measure doesn't go beyond what voters can enact through an initiative. If passed, it would be only the first step toward splitting the state, he said.

The initiative seeks to divide the state into Northern California, California and Southern California:

Northern California, containing the 40 northern-most counties — including Sacramento and San Franciso — stretching from the Oregon border to Merced County.

California, which would be made up of Los Angeles, Monterey, San Benito, San Luis Obispo, Santa Barbara and Ventura counties.

And Southern California, moving from Mono County along the state's eastern and southern borders to San Diego, and including Fresno and Kern counties.

Supporters gathered signatures from hundreds of thousands of Californians, and the secretary of state in June announced they had enough to get the effort on the general election ballot.

The justices' decision leaves 11 ballot measures for voters to weigh in November.

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