I agree with Force. Unions are part of a free market, provided the government does not take sides and simply enforces contracts and ensures no violence takes place. The public sector is not part of the free market and therefore the government can regulate rights to unionize and strike. In emergency-related positions this should include a ban on striking.

__________________
"Man lives in the sunlit world of that which he believes to be reality. But unseen by most is an underworld, a place that is just as real... but not as brightly lit... A DARK SIDE!"
-opening from Tales From the Darkside