Tax reform eliminated the deduction for union dues for tax years 2018-2025.

Per IRS Publication 529 Miscellaneous Deductions:

This publication explains that you can no longer claim any miscellaneous itemized deductions, unless you fall into one of the qualified categories of employment claiming a deduction relating to unreimbursed employee expenses. Miscellaneous itemized deductions are those deductions that would have been subject to the 2%-of-adjusted-gross-income (AGI) limitation.

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