Ferguson spoke at the José Martí Child Development Center in the Roosevelt neighborhood alongside early-learning advocates and child-care providers. He urged voters to reject the initiative, warning that its passage could lead to cuts in child-care subsidies and leave a $13 billion gap in the state budget.

That figure is also being cited by the initiative’s opponents as a potential loss to funding for education, child care and health care. The tax at issue has not yet begun collecting revenue: It is scheduled to take effect in 2029 and would apply a 9.9% rate to income above the $1 million threshold.

Rian Watt, who supports the “No” campaign, has argued that repeal would threaten funding for public services and that Washington’s tax system places a heavier burden, relative to income, on lower earners. Watt has cited estimates that the lowest-earning fifth of residents pay about 14% of their income in taxes, largely through sales taxes, compared with about 4% for the highest-earning 1%.

Supporters of I-645 say voters should be wary that the tax could eventually reach beyond millionaires. Jaime Herrera Beutler, a former congresswoman and spokesperson for the “Yes” campaign, has argued that the law does not explicitly bar future lawmakers from expanding it. The law’s stated purpose is to fund K-12 and higher education, health care and investments in Washington families and businesses.

Most retirement pensions would fall below the tax’s $1 million threshold, according to the information provided about the law. The tax has not yet been collected, even as campaigns for and against the repeal advertise across the state.

Ballots for the Nov. 3 election are scheduled to be mailed beginning Oct. 16. Ferguson urged voters to return their ballots by Election Day and vote no on I-645.