Alan Borsuk:

But changing benefits is, of course, a matter for labor negotiations, and the unions, particularly the Milwaukee Teachers’ Education Association, don’t want to change what they have.
Union’s response
Mike Langyel, president of the MTEA, said in a lengthy telephone conversation that the union just does not accept that there would be any savings by shifting more, if not all, employees to the lower cost plan. He called the notion that money could be saved this way “a fantasy” and accused Bonds and Superintendent William Andrekopoulos of engaging in “a theatrical production” aimed at making teachers scapegoats for MPS’ problems.
He said teachers earned their health insurance by accepting lower wage increases, going back more than 20 years, and members feel strongly about the Aetna plan. Langyel also questioned the honesty of the administration’s cost figures, although he did not give any specific instance that he believed was wrong.
“This is a calculated attempt by this administration to provide false choices,” Langyel said. “This will not solve the funding problems of this district one bit. . . .  The needs of this district are not going to be met on the backs of those people who are already sacrificing to be Milwaukee teachers.”
Langyel said that if all MPS employees were on the HMO plan, that would drive up the costs of that plan to a point that might eliminate the claimed savings. MPS administrators agree that the actual results of such a switch are not known and most likely would be less than the simple calculation that yielded the $47 million figure. Many older employees with higher health care costs are now on the Aetna plan, for one thing. But they do not agree there would be no savings.

This strategy is not unique to Milwaukee.