Arizona Supreme Court hears case challenging legality of Invest in Ed proposition 208 04/21/2021 Appellate court justices met at the Arizona Supreme Court for the hearing Thursday Oct.17 (Hailey Rein/DD) The Arizona Supreme Court met to hear Karen Fann v. State of Arizona on Tuesday, regarding the constitutionality of Proposition 208, a ballot initiative passed in the 2020 General Election. Prop. 208 is a ballot measure that increases the highest income tax rate in the state of Arizona by 3.5%, and intends to put the revenue toward state education. Invest in Education, a key proponent of Prop. 208 campaign, estimated that hundreds of billions of dollars could be raised for K-12 education in Arizona if the initiative passed.