Washington's 'Millionaires Tax' Faces Legal Battle: Is It Unconstitutional?

The new 9.9% tax on income above $1 million is sparking intense debate and legal challenges in the state.

Apr. 10, 2026 at 3:43am

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A serene, photorealistic painting of a government office building or political space, with warm sunlight streaming through the windows and deep shadows casting a contemplative mood, conceptually representing the legal and political debate surrounding the 'millionaires tax'.The legal battle over Washington's 'millionaires tax' highlights the complex relationship between government, taxation, and individual freedoms.McKenna Today

The legal battle over Washington's 'millionaires tax' has begun, with the Citizen Action Defense Fund arguing the 9.9% levy on income above $1 million is unconstitutional because it creates a tiered system of taxation that violates the principle of uniformity in property taxes. Former Attorney General Rob McKenna emphasizes the historical context, noting Washington courts have long held that income is property and property taxes must be uniform. Supporters argue the tax will provide essential funding, while opponents fear it could open the door to a broader income tax that could significantly impact the state's economy.

Why it matters

This case raises a deeper question about the balance between taxation and individual rights, prompting a discussion on the role of state governments in imposing taxes and the limits of their authority. The outcome will have significant implications for not just Washington but also for other states considering similar measures.

The details

The Citizen Action Defense Fund has filed a lawsuit in Klickitat County Superior Court seeking to invalidate the new 'millionaires tax' in Washington. The tax, which is not set to take effect until 2028, is a 9.9% levy on income above $1 million. The fund argues the tax is unconstitutional because it creates a tiered system of taxation, where income below $1 million is exempt while income above it is taxed at a higher rate, violating the principle of uniformity in property taxes.

  • The lawsuit was filed in Klickitat County Superior Court.
  • The 'millionaires tax' is not set to take effect until 2028.

The players

Citizen Action Defense Fund

The organization that has filed a lawsuit seeking to invalidate Washington's 'millionaires tax'.

Rob McKenna

A former Attorney General of Washington who emphasizes the historical context, noting that Washington courts have long held that income is property and property taxes must be uniform.

Bob Ferguson

The Governor of Washington who supports the 'millionaires tax', arguing it will provide essential funding for services like schools and healthcare.

Jackson Maynard

An opponent of the 'millionaires tax' who argues it could open the door to a broader income tax that could significantly impact the state's economy.

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What they’re saying

“The tax is unconstitutional because it creates a tiered system of taxation, where income below $1 million is exempt, while income above it is taxed at a higher rate.”

— Citizen Action Defense Fund

“Washington courts have long held that income is property, and property taxes must be uniform and limited.”

— Rob McKenna, Former Attorney General

“The tax will provide a substantial influx of funds, estimated at over $3 billion annually, which can be directed towards essential services like schools and healthcare.”

— Bob Ferguson, Governor

“The tax could open the door to a broader income tax, a move that many fear could significantly impact the state's economy and individual freedoms.”

— Jackson Maynard

What’s next

The lawsuit filed in Klickitat County Superior Court seeks to invalidate the 'millionaires tax' entirely. With the tax not set to take effect until 2028, the legal battle could drag on for years, potentially reaching the state Supreme Court.

The takeaway

This case raises a deeper question about the balance between taxation and individual rights, prompting a discussion on the role of state governments in imposing taxes and the limits of their authority. The outcome will have significant implications for not just Washington but also for other states considering similar measures.