Backers of an initiative that aims to repeal Washington’s new income tax of 9.9% on income over $1 million turned in 511,408 signatures Thursday to the Secretary of State’s office in Tumwater.

"When you go out and you talk to more than a half million people, you hear their voices and you hear what they're saying," Let's Go Washington founder Brian Heywood said in a speech just ahead of announcing the total number of signatures the group was turning in.

Let's Go Washington ran the initiative effort.

"Not one single person we talked to believes Olympia when they say this income tax is not coming for them. They know it's coming for them," said Heywood.

Let’s Go Washington needs just under 309,000 signatures to be verified for IP26-645 to qualify the measure for the November ballot.

Under Washington law, an Initiative to the People must collect signatures equal to 8% of the votes cast for governor in the last election. 3,861,388 Washington voters cast a ballot for governor in 2024. That means the initiative would require 308,911 signatures to qualify for the November ballot.

Turning in more than a half million signatures is expected to be more than enough to account for any duplicate signatures or people signing who are not registered voters, Let's Go Washington said.

During the Thursday afternoon event in Tumwater, several supporters of the income tax repeal effort addressed the crowd of about 100 people.

"This message today that you are sending loud and clear on this initiative is to say this is not what we want for the state of Washington. We know this [income tax] is going to drive down the state economy and add more cost burdens when we're already the fourth highest cost of living state in the entire country," said Building Industry Association of Washington Vice President Greg Lane.

Senator John Braun, R-Centralia, told The Center Square Republicans fought hard against the income tax during session, but were powerless to stop it.

"I think it's important for the people to get their chance at direct democracy. People are really upset about this and it's across party lines. This is a state that has rejected the income tax 10 times at the ballot and they are really made that Democratic majorities forced it through and they're anxious to get a chance to say no."

The initiative specifically targets the "millionaire's tax" passed by lawmakers, while attempting to keep other tax cuts in place.

According to LGW, the measure-

• Requires Olympia to fund the expansion of the Working Families Tax Credit, preserving tax relief for eligible low- and moderate-income working families.

• Protects future exemptions for household necessities such as grooming and hygiene products, diapers, and over-the-counter drugs.

• Provides small-business B&O relief, including the increased small-business tax credit and higher filing-relief threshold.

• Leaves in place the bill’s future rollback of sales tax on certain services, including provisions tied to retail-sale definitions and technical corrections for services newly subject to sales tax.

Supporters of the tax have amassed a war chest to convince people to reject the measure in the leadup to the expected November vote.

Washington Education Association President Larry Delaney put out a video statement June 1, targeting Heywood directly.

“Initiative 645 is bankrolled by a greedy hedge fund mogul named Brian Heywood, who moved here from California to shield his massive fortune from taxes,” said Delaney.

“The last time he attempted to give himself a big tax cut through a deceptive initiative, we resoundingly said no. Now he's at it again.”

Opponents of Washington's tax on income are also pursuing a lawsuit.

In April, a coalition led by Jackson Maynard and Citizen Action Defense Fund, that includes former state Attorney General Rob McKenna and former state Supreme Court Justice Phil Talmadge, filed a lawsuit in Klickitat County Superior Court. They argue the tax violates the state constitution, which treats income as property, which must be taxed uniformly.

"That is challenging more directly the constitutional defects in this proposal," said GOP Chair Jim Walsh, R-Aberdeen, in an interview with The Center Square at Thursday's event. "In those filings with the court, we're speaking to the defects in this income tax scheme and how it violates Article 7 of the state constitution, which is the section that defines tax policy in our state."

The Secretary of State will now take a statistical sample of petitions to validate signatures to determine if the measure qualifies for the November ballot.