Washington State Millionaires’ Tax Spared From Voter Referendum

Washington state’s new income tax on high earners won’t be put to voters, after the state high court ruled that it falls under an exception to the constitutional right to subject legislation to a popular referendum.

Gov. Bob Ferguson (D) signed the 9.9% levy on about 30,000 taxpayers who make more than $1 million a year into law March 30. The measure—referred to as the millionaires’ tax—will apply beginning in 2028 with the first taxes due in 2029.

The Washington Constitution’s referendum power carves out an exception for laws necessary for the support of the state government, which has been interpreted to include revenue-generating measures. The tax “undisputedly generates revenue for the state’s existing institutions and hence is” subject to the exception, the Washington Supreme Court held in a Monday order.

Therefore, the “Secretary of State has no mandatory, nondiscretionary duty to process the petitioners’ proposed referendum,” the court said.

Money manager Brian Heywood, who founded a political action committee called Let’s Go Washington, asked the high court to put the tax before voters this November.

Heywood’s petition didn’t challenge the constitutionality of the levy, which is subject to an ongoing lawsuit alleging that the measure runs afoul of a series of state supreme court rulings that require any state income tax to be be uniform and no higher than 1%.

The graduated income tax structure violates the requirement that taxation be uniform across those in the same class, according to the complaint filed in Washington Superior Court, Klickitat County. State law also bars taxing property, which has long been defined to include income, the challengers argued.

Opponents have argued that the tax will make Washington less competitive than other states and prompt high earners to relocate. Proponents point to Washington’s regressive tax structure and budget issues to argue that the tax, predicted to raise almost $4 billion a year, is necessary.

“This ruling states that the people cannot challenge via referendum any tax imposed by the legislature, removing any guardrails from the people on runaway spending,” Heywood said in a statement. The measure’s backers “now have a blank check to spend beyond their means and raise taxes later, and the people don’t get to weigh in,” he said.

Ard Law Group PLLC represented Heywood.

The case is Heywood v. Hobbs, Wash., No. 105220-1, mandamus denied 5/4/26.