Illinois state did have a ballot measure to amend the state constitution to replace the flat tax. Voters rejected it: https://news.wttw.com/2020/11/04/illinois-

Illinois state did have a ballot measure to amend the state constitution to replace the flat tax. Voters rejected it: https://news.wttw.com/2020/11/04/illinois-voters-reject-fair-tax-amendment https://news.wttw.com/2020/11/04/illinois-voters-reject-fair...