It is always hazardous to draw strong inferences from what happens at oral argument, particularly in a case of this nature. The justices know full well that the world will be watching, and thus will be conscious of how their questions might be perceived. (Look for the Chief to ask very tough questions of both sides.) Still, with that as a caveat, here are a few things to look for in tomorrow's proceedings on the Court's jurisdiction:
1. Does the Chief Justice or Justice Kennedy reveal some significant sympathy to Mr. Long's argument that the AIA deprives the Court of jurisdiction? Most have identified (I think rightly) these two justices as the critical votes. And they both--perhaps for different reasons--may wish the Court could simply avoid this matter altogether. Thus, any indications of their views on the matter are important, perhaps even dispositive.
2. Does Justice Scalia seem intrigued by the jurisdictional question? He is known as a hawk on Article III jurisdictional matters, a stickler for the limited role of federal courts. And he has voted that the Court lacks jurisdiction even in cases where the result has confounded his apparent ideological leanings. (Recall the case involving Utah's claim to an additional congressional seat.) Point 1 above notwithstanding, it is conceivable that Scalia, combined with the four Democratic appointees, could find the AIA argument persuasive.
3. Do the Justices' invoke the opinion of Judge Kavanaugh in Seven-Sky? There may be no more influential lower-court judge with the Court's present conservatives than D.C. Circuit Judge Brett Kavanaugh. And in a lengthy, scholarly opinion in Seven-Sky, Kavanaugh concluded (in dissent) that the AIA barred pre-enforcement challenges (at least by private individuals) to the minimum coverage provisions. If the justices are asking several questions referencing Kavanaugh's opinion, it could signal that the AIA argument has gained substantial traction.
4. To what extent do the justices ask about the states' Article III standing to challenge the mandate? This would only become an issue if the Court concludes that the AIA bars jurisdiction over the private parties' challenge to the mandate. So if this is a significant topic of discussion, it could mean a critical mass of justices think the Court needs to reach and resolve it.
5. Do the justices express any concern about what happens between now and 2015? If the Court dismisses the challenge to the minimum coverage provision on jurisdictional grounds, it likely means there could be no challenge in federal court until 2015, once the IRS has assessed a deficiency for someone failing to pay the applicable tax penalty. (Congress could amend the AIA in the interim, though, moving up the date.) Such a delay would leave a number of actors (large employers, health insurers, state and local governments, etc.) in a state of significant uncertainty, having to implement the ACA's requirements without knowing whether they will ultimately be upheld. Will the obvious costs of such uncertainty hanging over an industry comprising 18% of the U.S. economy dissuade the Court from going this route? If these practical implications are a significant object of inquiry, it points towards the Court going ahead and reaching the merits.
There are many more we could probably add to the list. But these are the five that jump out at me right now.