The dissent opinion is:
In opening his statement in dissent, Kennedy says: "In our view, the entire Act before us is invalid in its entirety.
Justice Ginsburg makes clear that the vote is 5-4 on sustaining the mandate as a form of tax. Her opinion, for herself and Sotomayor, Breyer and Kagan, joins the key section of Roberts opinion on that point. She would go further and uphold the mandate under the Commerce Clause, which Roberts wouldn't. Her opinion on Commerce does not control.
Justice Ginsburg would uphold Medicaid just as Congress wrote it. That, too, is not controlling.
The Affordable Care Act, including its individual mandate that virtually all Americans buy health insurance, is constitutional. There were not five votes to uphold it on the ground that Congress could use its power to regulate commerce between the states to require everyone to buy health insurance. However, five Justices agreed that the penalty that someone must pay if he refuses to buy insurance is a kind of tax that Congress can impose using its taxing power. That is all that matters. Because the mandate survives, the Court did not need to decide what other parts of the statute were constitutional, except for a provision that required states to comply with new eligibility requirements for Medicaid or risk losing their funding. On that question, the Court held that the provision is constitutional as long as states would only lose new funds if they didn't comply with the new requirements, rather than all of their funding.