The grant of a whopping 5.5 hours of oral argument on the various issues presented by the challenges to the Patient Protection and Affordable Care Act. As broken down by Lyle Denniston on SCOTUSblog, that's:
2) an hour on whether the tax Anti-Injunction Act forbids a pre-enforcement challenge;
3) an hour and a half on severability;
4) an hour on the expansion of Medicaid.
The really scary piece there is number 3. Why would the Court want to hear an hour and a half on severability if most of the Justices thought that the law was valid? Severability only arises if the Court first concludes that part of the law is invalid, and then must determine where, if at all, to cut off the rest of the law. So the fact that the Court wants more than a standard full oral argument on severability could be a signal that at least some of the Justices think they will need to reach the severability question.
Whether we read the grant on severability in that way depends in large part on the process used for adding time and limiting cert questions. The order list shows no dissent on this point but it would be highly unusual for any Justice to dissent publicly even if he or she thought that it was not necessary to hear so much about severability. Thus, it's possible that the separate grant on severability responds to just one or two Justices who take a special interest in the question. At the very least, we know that Justice Thomas -- given his narrow view of federal power -- will probably find it necessary to consider severability. So it's possible that this is not a signal about anything.
My own possibly polyannish view is that the effect of 5.5 hours of combined oral argument will be to make it more likely that the Court upholds the Act. Why? Principally because Justice Kennedy's prior votes and statements -- especially his concurrence in the Lopez case -- indicate that he thinks judicial intervention on federalism grounds should mostly be reserved for circumstances in which Congress has acted largely symbolically. Striking down the Gun Free School Zones Act in Lopez and the civil remedy provision of the Violence Against Women Act in the Morrison case were freebies. Those laws more or less duplicated state laws. By contrast, Justice Kennedy voted to uphold the laws at issue in the Raich and Comstock cases, where a vote to invalidate might have made a substantial difference on the ground. Five and a half hours of oral argument in the PPACA cases will underscore for Justice Kennedy that the stakes here are anything but symbolic. That in turn makes it less likely that he will vote to invalidate the law. And if he votes to uphold, that will be at least 5 votes for that outcome.