When the California Supreme Court unanimously declared a week ago that a highly controversial tax limitation measure could not appear on the November ballot, its proponents immediately cried foul.

They alleged that a court dominated by Democratic appointees had acted with political motives rather than legal reasoning, ruling that The Taxpayer Protection and Government Accountability Act was a revision of the state constitution and could not be proposed through a citizens initiative.

“Clearly, the state Supreme Court has now sent a signal that they are part of the progressive agenda in California, that we are a one-party state in California and there is no independent judiciary in California anymore,” Rob Lapsley, president of the California Business Roundtable, a major sponsor of the measure, told reporters.

In a statement, Jon Coupal, president of the Howard Jarvis Taxpayer Association — another sponsor — was equally critical, saying, “The seven justices of the Supreme Court yielded to the wishes of the political branches (and) put politics ahead of the state Constitution.

“It is now obvious that all three branches of California’s government — executive, legislative and judiciary — believe the government may decide how much money it needs and raise taxes accordingly, and the voters may not constrain them.”

Given their backgrounds, it’s reasonable to assume that most if not all of the justices may personally dislike a measure to redefine many fees as taxes and put very strict limits on state and local governments’ ability to increase them. But did that cause them to block the measure and cloak their bias in a blizzard of legal language, as the sponsors claim?

Read More: High court blocks anti-tax measure from California ballot

The justices seemingly anticipated that its motives would be questioned, stressing “the limited nature of our inquiry” very early in their ruling.

“We do not consider or weigh the economic or social wisdom or general propriety of the initiative,” Justice Goodwin Liu declared, adding, “The only question before us is whether the measure may be validly enacted by initiative.”

A careful reading of the 51-page decision acquits Liu and his colleagues of alleged ideological bias. It’s evident that in drafting the measure, proponents overreached by making very fundamental changes in California’s governance system, amounting to a revision of the Constitution that can only be proposed by the Legislature or a constitutional convention.

The court said the measure’s most obviously revisionist aspect would have compelled the Legislature to submit any tax increases to voters for ratification, thereby impairing legislative taxation powers that have been part of the state’s structure for its entire 174-year history.

“No speculation regarding potential future consequences is needed to conclude that the (Taxpayer Protection Act) is a revision on its face,” Liu wrote. “The measure would fundamentally restructure the most basic of governmental powers. The TPA would exclude the levying of new taxes from the Legislature’s control by requiring voter approval of all such measures.”

Some critics have suggested that the current court would have invalidated Proposition 13, the iconic 1978 property tax limitation measure. But Liu also addressed that, writing that Prop. 13’s changes “operate functionally within a relatively narrow range to accomplish a new system of taxation which may provide substantial tax relief for our citizens. We decline to hold that such a limited purpose cannot be achieved directly by the people through the initiative process.”

In other words, had the Business Roundtable and Coupal’s group proposed less sweeping changes in taxing authority, such a measure may have survived the legal challenge that Gov. Gavin Newsom, the Legislature and local governments mounted.

Given the legal uncertainty in California about who can levy what taxes on which activities, a clarifying ballot measure would be welcomed.

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,...