Proposals for the 2016 Massachusetts ballot are due Wednesday. Among those being submitted is one that would attempt to create a graduated income tax, an idea that state voters have rejected several times.

The proposal would raise the tax rate by four percentage points for personal income above a million dollars.

A coalition of union and community groups pushing for the change says it would bring in needed money for education and transportation. Former Northampton Mayor Clare Higgins is backing the measure. She argues Massachusetts has lower income taxes than many other states.

“We’re not this ‘taxachusetts’ of the past,” Higgins says. “What we do have is a system that treats different groups of taxpayers unequally, and this ballot question will help level that playing field.”

The proposal is now before the state’s Attorney General who will decide next month whether it can move forward. Because the measure would amend the state constitution, the earliest it could be on the ballot is 2018.

Correction: An earlier version of this story said the ballot question would increase taxes by four percent for people who make more than a million dollars a year. In fact, the proposal would increase the tax rate by four percentage points. The higher rate would not apply to the first $1 million in income.