By Nick Cahill
(CN) – Delivering a blow to a Silicon Valley billionaire, the California Supreme Court on Wednesday erased a November ballot measure proposing to divide the Golden State in three.

The six-justice panel unanimously agreed the “potential harm in permitting the measure to remain on the ballot outweighs the potential harm in delaying the proposition to a future election.”

Following a closed session Wednesday morning, the state high court directed elections officials to remove Proposition 9, dubbed “Cal-3,” from the November ballot. The panel says it will rule later as to whether the initiative by Tim Draper should be allowed to come before voters in the future.

The state cleared Draper’s measure for the ballot in June, finding proponents had collected more than the required 419,000 valid voter signatures. The ambitious initiative seeks to create three states – Northern California, Southern California and just California, which would cover Los Angeles and parts of Orange County.

The effort to freeze Draper’s measure is being led by the Planning and Conservation League, which asked the court last week to strike the initiative from the ballot. The group says the measure should be subject to higher qualification standards because it calls for drastic changes to the state constitution.

“The order is very unusual and dramatic because it takes the proposition off the ballot. The court has done that sparingly in the past,” said Howard Penn, executive director of the Planning and Conservation League, in a statement. “The only further questions are whether something like this could appear on future ballots and we are confident we will prevail on that when it is considered in the fall.”

In addition to future scrutiny from the high court, the proponents face a laundry list of logistical, legislative and legal hurdles to break up California.

Splitting up the nation’s most populous state would present monumental redistricting challenges, add four new U.S. senators and require the new state governments to figure out how to redistribute existing debts, water infrastructure and other assets.

If ultimately successful, it would mean the first split state since the Civil War, when West Virginia broke from Virginia in 1863.

The high court order states that while the justices traditionally review disputed ballot measures after an election, the conservation league has raised “significant questions” about the proposition’s validity.

“We have also made clear that in some instances … it may be appropriate to review a proposed measure before it is placed on the ballot,” the order states.

The panel ordered the parties to submit further briefs regarding the conservation league’s petition by Aug. 20.