Basically, it's about the affect the amendment might have because of the way the insurance business works. The restrictions requiring the abortion coverage to be a supplemental plan administered and paid for separately would be such a pain that the easier thing to do would be to not offer abortion coverage at all. And because there is nothing requiring them to offer abortion coverage, they won't.

The idea is that because of the affects that state and federal requirements have on demand and because it's cheapest to make the basic structure of the plan the same across the board, this might lead to companies dropping all abortion coverage from all their plans.

I guess you can buy it or not. As far as I can tell, the original bill said that if you got federal subsidies for insurance coverage, you could buy a plan with abortion coverage but you had to pay for the abortion coverage yourself, separately. The Stupak amendment says it can't be a part of the plan, it has to be a supplemental plan administered completely separately. The big difference, then, is not who pays for it but how the insurance companies would have to deal with it.

It's a difficult issue for me to understand because it deals in legalese and I am not a lawyer.