Don't BMI/ASCAP license fees go to pay artists' royalties? Don't stations have to pay a premium for their libraries? Sounds to me like artists (or more accurately, their record labels and music publishers) don't think they're making enough money, so they want to bleed stations for more. This will really hurt the small market stations whose budgets are stretched thin enough as it is (and I used to work for one, so I have painful knowledge of that fact).
The fact of the matter is, artists are getting a lot of money from things like store sales, iTunes, Amazon, and airplay. This "performance royalty tax" (which is not really a "tax" but more an increase in royalty payments) would hit every venue that uses recorded music, not just local radio. Party DJs, especially, would probably either go out of business or operate illegally (although I'd think that, just by buying a CD and performing it in a venue that does not charge admission, that would be enough for the artists).
The NAB is on record as being in opposition to the performance royalty bill, but apparently it's still in committee on Capital Hill. This blog has a good take on the bill and the shenanigans to try and get it passed -
http://www.broadcastlawblog.com/tags/performance-tax/.