I have not had time to read the Supreme Court’s health care reform decision or much in the way of coverage, but my understanding is that the lynchpin of the bill – the insurance mandate – was upheld by a vote of 5 – 4 with Chief Justice Roberts providing the fifth vote. He was willing to regard it as a permissible use of the federal government’s taxing authority – not, as the other supporting justices offered, as an extension of the federal government’s power under the commerce clause.
A brief explanation by Lyle Denniston here.
Update Here is additional explanation on the question of Medicaid expansion. I confess that I don’t know the particulars of what the Medicaid expansion provisions entailed. But, the Supreme Court held that it was unduly coercive in requiring states with Medicaid programs to either accept the substantial expansion or forfeit all Medicaid funding, even that which had previously been in place. A different majority held that the remedy for this violation was to simply read the statute as making participation in the expanded Medicaid program voluntary.
Due to the politics of the thing, I expect what we’ll see is that Democratically controlled states will take the federal money and offer more coverage for its poor citizens under Medicaid and Republican controlled states will decline to participate in the expansion.