Due to tax reform, the deduction for union dues expenses has been eliminated for tax years 2018-2025.
According to the IRS Instructions for Schedule A, p. 1:No miscellaneous itemized deductions allowed. No miscellaneous itemized deductions allowed. You can no longer claim any miscellaneous itemized deductions, including the deduction for unreimbursed job expenses. Miscellaneous itemized deductions are those deductions that would have been subject to the 2 percent of adjusted gross income limitation.