OLYMPIA, WA (MyBellinghamNow.com) – The legal battle over Washington’s so-called Millionaire’s Tax is heading back to court.

The Washington Supreme Court will hear arguments Tuesday, Sept. 1 in a dispute over ballot language tied to Initiative 645. The measure would repeal a tax on high-income earners set to take effect in 2026.

Activist Arthur West is asking the court to remove a required Public Investment Impact Disclosure from the ballot. The Washington State Standard reports West’s challenge was initially dismissed in Thurston County.

The disclosure tells voters the measure would reduce funding for K-12 education, higher education and human services.

West argues the law requiring the disclosure is unconstitutional, saying it improperly influences voters and infringes on Washington’s initiative process.

State attorneys say the disclosure is required by law and helps voters understand the financial impact of tax measures.

Other legal battles over the millionaire’s tax

The case is the latest in a series of court challenges tied to Washington’s new tax on high-income earners.

Initiative sponsor Let’s Go Washington unsuccessfully challenged the disclosure’s wording, arguing repealing the tax would increase, rather than decrease, available funding. A Thurston County judge rejected that claim earlier this month the same day West’s challenge was heard.

Earlier this year, the Citizen Action Defense Fund filed a separate lawsuit alleging lawmakers violated the state constitution by approving the tax. That case remains pending.

Let’s Go Washington also sued after state officials blocked a referendum on the measure because of an emergency clause in the law, but that challenge was also rejected.