is if the school in question meets state benchmarks? My view is this - teachers unions should only be allowed in schools that meet state benchmarks because if schools that don't meet state benchmarks are allowed to have teachers to unionize - then it allows them to stuff the school with more bad students - which will lead to a need for more $$$ and to hire more teaching assistants, which will create a self-reinforcing mechanism to hire more and more people to unionize.
An example is in this 20 minute speech:
http://hlmenckenclub.org/hlmc-audio/2014-bob-weissberg-the-left-and-education