Ballot Guide 2026: Washington's Initiative 645
Mountain States Policy Center has released a new ballot guide examining Initiative 645, which would repeal Washington’s new 9.9% income tax with a current statutory exemption for the first $1 million of income.
Written by MSPC Vice President and Director of Research Jason Mercier, the guide reviews the initiative’s ballot language, arguments from supporters and opponents, Washington’s history of rejecting income taxes, and the potential consequences for the state’s business climate.
The study highlights a distinction voters should understand: the $1 million exemption is established in statute, rather than protected by the state constitution. Lawmakers could change that exemption through future legislation, potentially extending the tax to additional taxpayers.
The guide also examines constitutional concerns surrounding the tax. It documents longstanding Washington court rulings treating income as property and explains why the new tax faces a separate legal challenge regardless of the outcome of Initiative 645. Washington voters have previously rejected ten income tax proposals.
Another central finding concerns the timing of revenue collection. The new income tax is scheduled to take effect in 2028, with revenues first collected in 2029. The guide explains that repeal would give lawmakers time to adjust future spending plans around existing revenue sources, rather than remove income-tax revenue currently funding government services.
The study also explores Washington’s changing business climate. State officials previously promoted the absence of a personal income tax as a competitive advantage. The guide cites an Association of Washington Business survey in which 45% of responding employers expected the new income tax to affect their businesses, while 22% were unsure.
The ballot guide provides voters, journalists and policymakers with an examination of what Initiative 645 would change, what the new tax would mean, and which constitutional and economic questions remain unresolved.
Mountain States Policy Center is an independent, nonprofit research organization serving Idaho, Montana, Washington and Wyoming. Its work advances free enterprise, limited government and individual liberty through fact-based public policy research.
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