To play devil's advocate, if a state goes broke paying ALL it's teachers and this isnt able to pay ANY of its teachers, is that better than a state laying off some of it's teachers so as to be able to keep others?
As to the OP, unions for the public sector are illegal currently and are opposed by many because of the influence and power such an organization could potentially wield.
Take a look at the California Teacher's Union. It's an extremely powerful organization both on behalf of the teachers but it's also grown to the point where it's started veering off on it's own agenda and lost sight of what it was supposed to do.
If there were some kind of mechanism in place to keep a union for government employees from becoming a political force, I'd be for it.
so you have no problem with the dictatorship over workers that exists in all workplaces? then you're not for the liberation of the working class friom oppression and exploitation. Every worker has the right to self-manage -- control -- their own work.
Almmost all unions, whether in public or private sector, in the USA have problems with an overpaid bureaucracy that wields too much power. That's a completely separate question from organizing rights for workers.
Why should public sector workers have less say in the governance of their communities than anyone else?
As to teachers unions, they were formed as a protection against arbitrary authority, just as in private industry. Teachers could be fired for no particular reason, or for political reasons.
The emancipation of the working class must be the work of the workers themselves.