Union dues (and initiation fees) are deductible as unreimbursed employee expenses. Those are an itemized deduction subject to the 2% of AGI limitation (ie: only amounts over 2% of AGI are deductible).
That 2% limitation includes ALL of your 2% Miscellaneous deductions, which include other unreimbused employee expenses, tax prep fees, investment fees, etc.
Your union will probably give you an annual statement indicating what percentage is lobbying so that you can remove that (if they don't, you can ask them).
The IRS gives some examples of other items that might also be deductible as unreimbursed employee expenses.
http://www.irs.gov/publications/p529/ar02.htmlBasically, you're going to end up in the deductibility zone for 2% Misc deductions with your union dues alone, so it's probably worth it to you to save receipts for any and all other 2% Misc deductions.
For example:
Agi = 50,000
2% of AGI is $2000
So you need more than $2000 of Misc deductions (in addition to having enough total itemized deduction to make itemizing worthwhile).
Assuming you have enough to itemize in total, you also have:
$2000 in Union Dues
$500 in Union initiation fees
$100 in deductible Meals work-related ($200 total, 50% of which are deductible)
$100 for tax software
$100 for a work-related license
For a total of: $2800 in 2% Misc deductions
Due to the 2% limitation, $800 will end up being deducted as itemized deductions.