I think the general analysis of the Justices' positions is a little off. But before I go into that, I want to say two things about the ACA:
First, when given the choice about what model to use to take care of a significant drain on the US economy, Congress had essentially two to choose from - Medicare (VA, etc.), a single payer system of general coverage; or the FEBB (Federal Employee Benefit Plan), which is what covers all full-time federal employees, and members of Congress.
Second, they chose the latter, because it was most familiar, has been successful for decades, provides for choice for all participants, and was the method that was advocated for years by Republican and Conservative advocates, and the expectation was that it would therefore garner bipartisan support. I think the complete about-face by the GOP and Conservatives, and the outright vitriol, hypocriticality, and complete dishonesty of the opponents (some of whom are now Presidential aspirants) shocked Obama, the administration, and the Democrats. They thought they were compromising by giving the GOP what it wanted, and had no idea (initially) about how completely debased the party had become.
Now, to the merits of the arguments. This case should be deferred under the AIA, not because it is a tax, but because penalties cannot accrue until some future action takes place. This is a much stronger argument than most people here (and elsewhere) understand. It is not a "taxation/non-taxation" issue, it is enjoining something that hasn't had an impact and whose potential impact is therefore completely speculative. If we get beyond the AIA issue, which it appears we will, it is because the Justices want to address the merits, not because the law requires - or even allows - them to. It would not be the first, and will not be the last, time they do this, because many of them are driven by ideological imperatives not connected to precedent or the rule of law.
On the Commerce Clause issue, this is almost a no-brainer, from a precedential status. Congress has for decades, and the Supreme Court has endorsed, a broad application of the Commerce Clause when a significant economic activity is occurring. This is an issue that affects nearly 18% of our economic activity, and is unarguably of an interstate character. There is no question that the commerce clause applies. The question then becomes if the mechanism is unprecedented, because they call it a mandate. Well, it is not unprecedented, or even extraordinary. The fine line that the objectors are trying to create has not existed for 80 years. They argue that we are trying to force people to enter a market, whether they want to or not. Well, we do that already in a myriad ways - Social Security, for example; mandatory car insurance, for another. Is it different when the State does it, than the federal authority? Not in this instance, because it is within the commerce clause authority of Congress.
So, the basic questions are: 1) Can Congress legislate in the sphere of medical health coverage? Explicitly, yes. 2) Can Congress Mandate activity from citizens? Obviously, yes - for example, you have to get a SS card for a child before that child can even work, or pay a penalty if you fail to do so. 3) Can Congress require one to obtain an insurance policy, or pay a penalty for not doing so? In the same way that States have been doing it for decades.
Finally, there is the matter of where the Justices might come down on each of these questions. I think the decision to bypass the AIA will not be universal, but will probably be 7-2 in favor. There are too many Justices that want to get to it, regardless of the damage that will do to AIA precedents. With regard to the mandate, I think that the vote will be 6-3 in favor of upholding the law, with Kennedy and Roberts joining the majority, and Roberts authoring the lead opinion. There will, of course, be 5 separate opinions, at least. Ginsberg, Kagan and Sotomayor will write a concurrence. Kennedy will write separately. Scalia will write separately, concurring and dissenting and either Alito or Thomas will author a dissent that they join together.
