Either in a few minutes or on Thursday [update: it won’t be until Thursday], we will know what the Supreme Court decides in the case of the Affordable Care Act. They could go in a variety of directions, from upholding the entire law to taking the whole of it down, to a number of options in between (indeed, the Court could rule the individual mandate unconstitutional but keep the penalty for not purchasing insurance as proper under the taxing power, which would constrain the commerce clause in future legislation but effectively change nothing about the Affordable Care Act).

Though most legal scholars believe the mandate to be constitutional, most of them now believe the Court will reject it. And the reason is as simple as counting to five. In most – not all, but most – rulings on the mandate, the primary indicator of a judge’s ruling was where he or she fell politically. Democratic appointees found the mandate Constitutional, and Republican appointees didn’t, by and large. There are a few exceptions to this rule, but for the most part, it has held. And with five conservative justices on the Court, a ruling that falls in line with this precedent would suggest taking down the mandate.

I liked how Brad DeLong described this as a “Constitutional moment,” one of those times where the Court decided to assert its power and change the law in a fundamental way. And he writes that, in all those other times, the change was ideologically driven, rooted in fundamental divides over how the country would act. This health care ruling is different:

The interesting thing about the Constitutional Moment that now perhaps looms is that it is the first one in which the stakes are purely partisan, and purely political. The probable Supreme Court majorities in the ACA case have shown no inclination to restrict congressional power when it is a matter of exceeding black-letter patent clause authority to provide a payoff to Disney or to prohibit the medical use of marijuana–and will show no inclination to revisit and change those decisions in the future.

I think that’s absolutely right. Regardless of what you think about the mandate, we know who DOESN’T think the same way – the five members who are likely to decide this issue on the Court. They aren’t interested in limiting federal power. They’re interested in limiting this law.

That in theory should drive reactions to the ruling, particularly rhetorically. The Court has now teed up three rulings in the past decade – Bush v. Gore, Citizens United and now, potentially, this one, which show inescapably the culmination of a Federalist Society-driven partisan bent, as well as a fealty to corporate power. The Court acts as a backstop, to resist in a partisan way whatever comes out of Congress that their side determines as an overreach.

I don’t go so far as James Fallows to suggest that this is a coup. But I do believe that there are, under the current construction of the Court, partisan limits to how government can act, in a manner that we haven’t seen in some time.

As for those reactions, on the Democratic side it will probably consist of a lot of finger-pointing and an ill-fated policy response.