I realize the post is old but its very difficult to find any information regarding this issue. Live and file in Illinois (rate is 4.95%). Have gambling winnings from Indiana (rate is 3.23%). Illinois does not allow a deduction for tax paid to another state for gambling (until 2020) So, I paid BOTH state’s tax on the same income. Double taxation. I'm wondering how that is legal? I thought the supreme court ruled it wasn't in 2015 (two states can't tax the same income).
