Deducting union dues if self-employed and W-2 employee

[musician98]

I have a full-time day job but I also work on the side as a musician. For my music work, one orchestra pays me as a W-2 employee, and the other groups send 1099s. (I also report the income that doesn't get a 1099 or W-2.) For the W-2 orchestra, I joined the music union because the orchestra will pay you slightly higher wages if you are in the union. That is the reason I joined the union. (They do not require you to join it.) Theoretically, there are also other benefits to being in the union, and being a member gives you access to resources that are helpful for the profession. Since I am self-employed for some of my music work, can I deduct the union dues on my taxes? Or is that not allowed because I only joined the union because of the W-2 orchestra? 

[Mike9241]

One rules for deducting business expenses (non W-2) is that they must be ordinary and necessary (though I admit various tax courts interpret this differently depending on the facts and circumstances involved). So the question is are there any benefits to being in the union for your non-W-2 work?

as an aside, in some cases, business owners will own and use extremely expensive vehicles in their business that really aren't necessary, but the IRS lets this slide. This leaves the question of exactly what O&N means. A Chevy can get you to the same location that a Rolls-Royce can 

[musician98]

Thank you for the advice! I've used the union to learn some useful information and sometimes I refer to their resources to help with non-W-2 gigs, although that might not count as strictly necessary.