By Simone Carter
The Olympian (Olympia, Wash.)
(TNS)
Just hours ahead of Gov. Bob Ferguson’s expected signing of the income tax on high earners, official plans for a lawsuit against Senate Bill 6346 were announced.
The Citizen Action Defense Fund (CADF) said in a Monday morning news release that it’s gearing up to file suit against the controversial soon-to-be law, which supporters have dubbed the “millionaires tax.”
Its lead counsel? Former Washington State Attorney General Rob McKenna.
CADF says that it retained McKenna to spearhead the anticipated legal push challenging the measure’s constitutionality; a suit is likely to be filed “within the next few days,” according to the March 30 news release.
McKenna said in the release that the state’s constitution and courts have long made clear that progressive income taxes are unconstitutional, and that income is considered property.
“If the State proceeds with the new income tax, it will create a direct conflict with binding precedent and the constitutional protections that safeguard taxpayers,” McKenna continued. “We are preparing to challenge the tax in court.”
Then, just before noon on Monday, the conservative political group Let’s Go Washington announced that it is filing a referendum to repeal the income tax, citing constitutionality concerns.
Ferguson’s office did not immediately return McClatchy’s request for comment.
At a Monday morning event at the state Capitol building, Ferguson signed into law the income tax, perhaps the most contentious bill yet to reach his desk.
SB 6346 was the center of fierce debate throughout the just-wrapped 2026 legislative session. It would impose a 9.9% levy on annual household income over $1 million.
The tax would take effect in 2028 with initial collections to come the following year. It’s estimated that the measure would generate roughly $3.5 billion in revenue annually.
Recommended Articles
Democrats have argued that the tax is needed to make the wealthy pay their fair share, and to ensure that the state can continue funding key services including education and health care. Lawmakers tacked on tax-relief provisions, too, including the elimination of sales taxes on diapers and hygiene products.
Republicans, meanwhile, fear that the tax is a slippery slope. They worry that, imposed on those with over $1 million in income today, it could be lowered to apply to more Washingtonians later.
McKenna and CADF say the legislation would create a graduated tax on income, thereby running afoul of the “uniformity requirement and constitutional limitations on property taxation” under the state constitution.
CADF Executive Director Jackson Maynard said in the release that Ferguson and state lawmakers have opted to ignore both settled case law and the constitution.
“This lawsuit is about upholding the rule of law and ensuring that Washingtonians are not subjected to an unconstitutional tax scheme,” he said.
CADF isn’t alone in taking aim at the legislation. The Washington State Republican Party has said it plans to try to repeal it via initiative.
Ferguson has said that he thinks the tax is constitutional. The Spokesman-Review reported that the governor said at a Dec. 23 news conference: “I wouldn’t be supporting a proposal unless I felt confident that we could navigate that path, and also, there’s going to be a public conversation. If this goes forward, there’s going to be a public conversation, there’s no doubt about that, and the people will have their chance to weigh in on it as well.”
Ferguson spoke at the bill signing Monday, but didn’t stop to take questions from McClatchy and reporters from other news outlets.
He told those gathered that Washington is home to one of the most regressive tax structures in the country. The wealthiest residents pay a much smaller portion of their income toward taxes than those with lower incomes, he said.
That disparity is worsened, he said, by President Donald Trump’s move to enact tax cuts for the rich amid decreases to services like food assistance and health care.
“While Washington, D.C. is taking us backwards, the good news is here in Washington state, we’re moving forward, everybody,” he said, eliciting applause.
Senate Majority Leader Jamie Pedersen, a Seattle Democrat who sponsored SB 6346, said at Monday’s conference that revenue from the tax will help make the state more affordable for small businesses and families, and will help to fund child care, public schools, health care and higher education.
“With this bill, we’re going to begin to right a historic wrong that has plagued our state for nearly 100 years and made our tax system one of the worst and most regressive in the entire country,” he said at the conference.
Maynard told reporters after the event that he doesn’t think the Supreme Court will overturn long-standing precedent regarding an income tax. He noted that there will soon be five justices on the ballot—usually just three are up for election at a time—serving as an opportunity for voters to have a say in the high court’s composition, “which I think will be very interesting in relation to this case.”
Anti-tax activist Tim Eyman, speaking with reporters following the signing, called SB 6346 a “really bad bill—awful, horrible.”
Eyman said he goes to such events because he wants to represent Washingtonians who are working and don’t have time to come to Olympia. He held onto a printed itinerary that featured an autograph from the governor, including the note: “Tim—see you in court!”
In Eyman’s view, the bill won’t ultimately survive efforts to upend it.
“They won this battle,” Eyman said, “but they’re going to lose the war.”
Photo caption: Former Washington Attorney General Rob McKenna in 2013. (Via Facebook page of Rob McKenna)
_______
© 2026 The Olympian (Olympia, Wash.). Visit www.theolympian.com. Distributed by Tribune Content Agency LLC.
Thanks for reading CPA Practice Advisor!
Subscribe Already registered? Log In
Need more information? Read the FAQs
