The state Senate acted on the legislation Monday. It now becomes law without the governor's signature.
Last year, a tax cut bill failed when Nixon, a Democrat, vetoed it, and Republicans failed to muster the votes needed for an override. The new bill ties tax cuts to growth in state revenue, and supporters say it will not hurt essential state programs.
But Nixon says that buried deep in the bill is language that could eliminate the tax on all incomes greater than $9,000, costing the state $4.7 billion in revenue. Democrats also say the state should fully fund aid to education before cutting taxes.
“The reality is, at the end of the day, we wanted to make sure that folks understood that we are going down a road where we have made a decision to cut taxes before we meet our obligation to education,” Jolie Justus of Kansas City, the Senate minority leader, said.
Under the bill, the first cuts to top income tax rates would come in 2017, with the rate dropping from 6 percent to 5.5 percent over five years. The cuts would take effect only if revenues are still growing.