The California Supreme Court ruled Thursday that a ballot measure aimed at making it harder for the state and local government to raise taxes would not appear on the ballot, siding with the governor in the case.

The measure in question would have, if passed, required the voters to approve any tax increases passed by the state legislature. It also would have required certain local tax increases to receive a two-thirds majority in the polls. As it stands now, they require a simple majority to pass. The measure also would have retroactively applied to tax increases that have been approved since January of 2022.

Governor Newsom sued to block the measure, saying it would disempower the legislature and hurt local governments while supporters of the measure contested that it would give voters more control over taxes.

The court sided with Mr. Newsom, with Justice Goodwin Liu writing that it would “substantially alter our basic plan of government.”

Supporters of the measure called the ruling “the greatest threat to democracy California has faced in recent memory,” noting the measure followed the rules to qualify for the ballot by securing enough signatures from the public before the deadline.

“The governor has cynically terminated Californians’ rights to engage in direct democracy despite his many claims that he is a defender of individual rights and democracy,” the Taxpayer Protection and Government Accountability Act campaign said in a news release.