Missouri residents are voting on Tuesday on whether to phase out state income tax and allow lawmakers to expand sales taxes, one of several ballots this year that will help shape a growing divide in red-state and blue-state income-tax policy.

Republican-led states have been racing each other to cut or eliminate individual income tax, while some blue states are attempting to raise income tax on the wealthiest residents -- usually on annual income over $1 million.

The ballot measure in Missouri asks voters whether the state should phase out the graduated income tax, which has a top rate of 4.7%. To make up for the lost revenue, the measure would allow legislators to increase sales taxes and expand them to more purchases, including to services such as television streaming and auto repairs, which Missouri currently doesn't tax.

Missouri Republicans backing the measure say that it will make the state a more attractive place to live and work and that Missouri must slash income tax to compete with other states that have done so. Jon Patterson, Missouri's Republican House speaker, has said he wanted to "avoid the risk of being left behind."

The Missouri Budget Project think tank estimates that state sales tax collections would need to increase from $3.3 billion to $11.8 billion annually to fill the gap. That would mean potentially tripling Missouri's general sales tax rate from the current 3% to 10.7% or significantly expanding the type of purchases on which sales tax is levied, the group said.

Such a shift "would increase taxes on low and middle-income Missourians -- while giving a massive tax break to the wealthiest," the group said in a recent report.

Roughly two dozen Republican-led states have lowered their top income-tax rates since 2020. Mississippi and Oklahoma, among others, put themselves on paths to eliminate personal income taxes. South Carolina is setting a course this year to drop its top income-tax rate to 1.99%.

Several states, including Kentucky and West Virginia, have triggers in place that could theoretically eliminate their individual income taxes, according to Jared Walczak, senior fellow at the Tax Foundation, "though in practice it's not clear that the triggered reductions would take them that far," he said.

Democratic-controlled states are moving the opposite way, pushing to increase taxes on top earners to combat income inequality and plug budget holes expected from Republicans' cuts to federal health and nutrition assistance programs. Washington state in March enacted a 9.9% tax on income over $1 million, which will be used to fund child care programs, free school meals, tax credits for working families and tax breaks for small businesses. Washington previously lacked any state income tax.

In April, Maine adopted a new 2% surcharge on annual income over $1 million. In Colorado, a coalition of progressive groups is collecting signatures for a possible November ballot measure that would scrap the state's flat income tax and establish a graduated system, raising taxes for people making more than $500,000 a year and lowering them for people under that level.

And in California, the Democratic Party has endorsed a proposed billionaire tax, which would levy a one-time 5% tax on the wealth of those with net worths of more than $1 billion. Supporters say it would raise some $100 billion to help offset looming federal cuts to Medicaid. California voters will decide whether to approve or reject the ballot initiative in November.