Robert Whitcomb, of the ProJo editorial page, has written an editorial entitled Public and Private Unions, which includes this excerpt:

I write as an ex-member of three unions, in one of which I was grievance chairman. Private-sector unions, such as these, are different creatures from public-sector unions.
In the private sector, the complexity, churn and competition of capitalism — as well as anti-trust, anti-corruption and other laws — restrain companies and the unions that dwell with them. After all, companies rise and fall, as do whole industries, and they take their unions with them. But then unions themselves are businesses, selling labor…
But public-sector unions are something else: They’re virtually untrammeled monopolies. They control services to which the public has few alternatives. That politicians benefit financially and otherwise from public-sector unions, and vice versa, further strengthens the monopoly. Together, the two groups do pretty much what they want, whatever the citizenry’s needs and desires.
Thus, to raise concerns about public-sector unions is not to be “anti-union.” Nor is it to condemn civil-service protections for public employees. It is simply to face reality.

ADDITIONAL INFORMATION:
Bankrupt pensions, extraordinary healthcare insurance benefits, related issues with private and public sector unions, and the misguided incentives that exist in public sector taxation have been discussed previously on Anchor Rising:
Public Sector Issues
Misguided Incentives Drive Public Sector Taxation
Bankrupt Public Pensions: A Time Bomb That Will Explode
Why Truly Free Markets & Timely, Transparent Information Are Needed to Protect the Freedom of American Citizens
RI Public Pension Problems
The Cocoon in which Entitled State Employees Live
The Union’s Solution for the Future: Get More People in Unions
Bankrupt Public Pensions, Part II
How Public Pensions Make People Well-Off at Taxpayers’ Expense
Private Sector Issues
If You Won’t Deal With Economic Reality, Then It Will Deal With You
Underfunding Pensions, Public and Private, can Hurt Taxpayers
Why Truly Free Markets & Timely, Transparent Information Are Needed to Protect the Freedom of American Citizens
Outrageous Employee Compensation Liabilities Continue to Haunt General Motors; Will American Taxpayers End Up Paying the Bill?
Why the Big Three Auto Companies Could Easily Fail