Language confusion often gets in the way of communication. We speak English, withdrawing words from the same bank, but assign different meanings, sometimes depending on our own beliefs and sometimes because we don't understand that the same word can have two different meanings. I find this to be the case with the term "union."

Unions, both in private and public context, may share similar structure, and even function, but the circumstantial differences need to be mentioned.

Much comes down to a basic bargaining model. Imagine Bill, an employer, is looking to hire Bob, a potential worker. Together, they would produce $8/hour. Without entering into contract, Bill would get nothing. Bob has an alternative that for $7/hour. So $7 is the point where Bob would walk away. To enter into a contract, the agreed upon wage would be between $7 and $8.

The main role of unions is to help workers get a greater share of the surplus. In this case, the total surplus is $1 (total value is $8, subtract $7 [Bob's point of walking] and $0 [Bill's point of walking]). Alone, Bob may get $0.15 of the surplus (for a wage of $7.15), but with a union, the union rep is a better bargainer and may get the worker $0.50 or so ($7.50).

Circumstances are different in the public sector. Workers are not hired to produce revenue. Public sector employees are paid from a source irrelevant to their production: taxes. Employees may have a next best alternative (lower limit to their pay), but they have no upper limit. Therefore, no total surplus to allocate between the employee and the employer exists.

Public unions would be similar if a rep for government workers negotiated with a rep for taxpayers. Public employees would not "make money" for taxpayers, but provide services worth up to $x. That would be the total surplus, and negotiations could occur for how that surplus gets allocated.

Senator Moynihan said, "You're entitled to your own opinion, not your own facts." I am not saying whether public employee unions are good or bad, but they clearly are different from private unions.