The Supreme Court in Washington State has struck down a charter school law that was passed in a 2012 referendum with support from Bill Gates and other philanthropists, the Seattle Times reports.

On September 4, the court ruled 6-3 that the law allowing publicly funded but privately operated charter schools violates the state constitution, which restricts the use of public school funds to “common schools.” Charter schools, whose governing boards are appointed by school founders rather than elected, do not qualify as such. It is not clear how the ruling will affect the charter schools that have opened or are opening this fall. The parties have twenty days to ask the court to reconsider its decision before the ruling becomes final.

Washington voters had rejected three previous initiatives to open charter schools in the state before narrowly approving Initiative 1240, which was backed by more than $3 million from Gates, $1.7 million from Walmart stores heiress Alice Walton, $1 million from entrepreneur Nicolas J. Hanauer, and $750,000 from the parents of Amazon.com founder Jeff Bezos. In 2013, a coalition of organizations that included the Washington Education Association, the League of Women Voters of Washington, El Centro de la Raza, and the Washington Association of School Administrators argued that the law “improperly” diverted public school funds to organizations that are private and “not subject to local voter control.”

“The Supreme Court has affirmed what we’ve said all along — charter schools steal money from our existing classrooms, and voters have no say in how these charter schools spend taxpayer funding,” Washington Education Association president Kim Mead told the Times.

Not everyone welcomed the decision, however. Joshua Halsey, executive director of the state charter-school commission, criticized the timing of the court’s ruling. “The court had this case in front of them since last October and waiting until students were attending public charter schools to issue their ruling is unconscionable,” said Halsey. “We are most concerned about the almost one thousand students and families attending charter schools and making sure they understand what this ruling means regarding their public-school educational options.”