Having Congress charter a health insurance "cooperative" is just another way of creating a new government-run program that would drive private insurers out of business.
The definition of a cooperative is a health plan governed by its enrollees. Since a government chartered co-op won't have any enrollees at first, it will be governed like any other government program. So when the Obama administration and congressional Democrats say, "We're going to create a co-op," what they mean is, "We're going to create a new government health program but we will turn it over to the members in five years. We promise."
As I explained in a recent Cato study, a government-chartered co-op would become just another Fannie Med:
It makes no difference whether a new program adopts a “co-operative” model or any other. The government possesses so many tools for subsidizing its own program and increasing costs for private insurers—and has such a long history of subsidizing and protecting favored enterprises—that unfair advantages are inevitable.
Who was it that said that thing about putting lipstick on a pig?