Union membership & College Degrees

After the dust-up in NJ the other day between Gov. Christie and the poor teacher complaining about her income level being inadequate, I began to wonder. What professions/employment categories where a college degree is require/preferred are openly dominated by unions - and why?

The obvious ones are public school teachers and local, state, and federal 'middle managers'. I know there are variations and exceptions here, but we all know that the SEIU, NEA, NTA, et al live and thrive here. Are there other industries that unionize their 'professional' employees? Other than government, are engineers unionized at Boeing or Intel? Are physicists or mathematicians unionized anywhere? Don't all those people compete with each other for their jobs based on their individual skills and capabilities? Why do teachers and government 'professionals' need union 'protections' that we have historically associated with the lower working classes. And now demand to be treated as equals with those who have no job guarantees or protections. Is it a coincidence that all those union jobs are net negatives on the economy - producing no revenue on their own, but relying on the private sector being taxed to provide their income.

I'm open to someone telling me other unionized college grads that need such protection. Don't bother talking about professional athletes - they may be unionized, but they each negotiate their own contract.