NPR [npr.org] reports today on court decision United States of America v. CALIFORNIA, et al. Intervenors - Defendants. [ca.gov]
In his 55 page summary Judge Reed O' Conner argues that SCOTUS affirmed Obamacare because the majority interpreted it as a tax, but only because they could encapsulate it within the scope of a tax. Without the individual mandate it could no longer be regarded as a tax, and therefore the exceptions that SCOTUS itself had raised invalidated the remainder of the law.
The link to the PDF of the actual decision above is worth a read. While the main stream parties will misconstrue this, the argument itself is well written and exceptionally well documented.