The proposal, formally titled the "Allow for Graduated Income Tax Amendment", appeared on the ballot in the November 3, 2020 election in Illinois as a legislatively referred constitutional amendment striking language from the Constitution of Illinois requiring a flat state income tax.

[6][7] The United States federal government, via the Internal Revenue Service, uses a graduated income tax.

[10] In its own analysis, the federation projected that the loss of revenue "would dramatically destabilize Illinois' already weak financial condition."

Allowing 2014 law to continue would reduce the median taxpayer's bill by $689 per year, an additional savings of $386 versus the Harmon rates.

[18] Other speculative proposals had called for top marginal rates as high as 11 percent, but they were not introduced in the state legislature.

[12] Proponents argued that Harmon's rate schedule would provide tax relief to 94% of Illinoisans.

Opponents and skeptics contended that was misleading since the current law in 2014 prescribed a decline in the personal income tax rate to 3.75 percent in 2015, after the expiration of a 2011 temporary surtax.

[22][23][24] The passage of the resolution placed the proposed amendment on the ballot in the next general election on November 3, 2020.

[26][27] If the amendment had been approved, Senate Bill 687 would have raised taxes on Illinois taxpayers with a taxable income over $250,000.

The state government would then have been allowed to change income tax rates through the normal legislative process.

[34][35] The Illinois legislature proposed a new set of income tax rates in Senate Bill 687, which was enacted shortly after the constitutional amendment was approved to be placed on the ballot.

This legislation would have taken effect on January 1, 2021, if voters had approved the constitutional amendment in the November 2020 election.

Vote Yes For Fairness was formed by Quentin Fulks, who is also the head of Think Big Illinois and was a staffer on Pritzker's 2018 gubernatorial campaign.

[42] Vote Yes for Fair Tax was headed by John Bouman, president of the Shriver Center on Poverty Law, and received donations from a number of labor unions and community organizations.

[89][35][90] Labor unions, activist groups, and Democratic Party politicians have pointed to estimates that the new tax rates would increase state revenues by $3.4 billion annually while reducing the burden on lower-income families, arguing that increased revenues could be used to fund schools, healthcare, and public safety.

[91][92][88][93] In endorsing the Fair Tax proposal, a coalition of 125 labor unions in the state argued that it would reduce economic inequality and would enable increased funding for public education and healthcare.

[101][92][102] The Illinois Chamber of Commerce argued the new tax system would hurt business and push wealthier earners out of the state.

[92] Opponents have also argued that the state government cannot be trusted to appropriately spend the additional funds that would be raised, and that the proposal gives lawmakers a "blank check.

"[103][104][101][102][105] For example, the organization Vote No Blank Check have pointed to the corruption scandal surrounding Commonwealth Edison and Illinois House Speaker Michael Madigan in their campaign against the ballot referendum.