The key 14th Amendment issue seems to be whether Congress can come to its own judgment on the issue of whether a particular abortion procedure is medically necessary, and what review the courts should apply. My prediction there is that Roberts-Alito-Scalia-Thomas will agree that a very wide deference is owed to legislative judgments, that Stevens-Ginsburg-Breyer-Souter will say that Congressional judgment is owed little deference, and was wrong here, and that Kennedy will write the opinion of the court saying little deference is owed, but Congress got it right this time. We will see if the crystal ball holds up.
What would I do? Well, unlike people on the left of the abortion issue, I think the conflict-of-interest inherent in a doctor who performs abortions deciding what is medically necessary is a legitimate and important legislative concern. I think this is something the political process should decide.
But which political process? The state or the federal? This strikes me as precisely the sort of divisive cultural/moral issue that should be in the hands of individual states: there is just no need for a single, federally-mandated solution.
It should be noted that the federal partial birth abortion ban is based on the "Interstate Commerce" clause of Article 1, a clause which has been bent out of all recognition by post-New Deal "progressive" jurisprudence, into a pretty much all-encompassing grant of federal power. The Rehnquist court made some baby steps in cutting back on this theory when it comes to non-economic regulation, but except for Clarence Thomas,* there were at best fairweather federalists on that court. It will therefore be interesting to see what Alito and Roberts do.
According to Marty Lederman, John Paul Stevens, the leader of the liberal bloc, was the one to raise the federalism issue in oral argument. He asked how Interstate Commerce could apply to an abortion clinic that does not charge for its services. The Solicitor General cleverly suggested that this issue could only be dealt with in an "as-applied" challenge, since it might be that the federal statute, properly interpreted, would not apply for non-constitutional reasons.
A more fundamental question -- it seems to me -- is whether the federal government should be allowed to regulate something for patently non-economic reasons, just because it might be bought and sold. That strikes me as the punchline to a reductio ad absurdum, but sensible Americans tell me that even the wild-eyed federalists on the court believe it.
Interestingly, though, Justice Scalia is on record (non-judicially) saying the federal government has no jurisdiction over abortion:
[I]f a state were to permit abortion on demand, I would -- and could in good conscience -- vote against an attempt to invalidate that law for the same reason that I vote against the invalidation of laws that forbid abortion on demand: because the Constitution gives the federal government (and hence me) no power over the matter.
I would hope that all of Thomas, Kennedy, Alito and Roberts would agree with this, in which case the federal law ought to be considered unconstitutional by everybody.
*Thomas is apparently not present for the oral hearing because he is sick, but will rule in the case. This is a bit shocking to my own lawyerly sensibilities, so I wonder if my American readers can tell me whether this is common in American courts.