A friend recently posted an article on his site  regarding what many in the "Justice for All" camp take to be the strongest argument for the legal and moral permissibility of abortion. The article is written by Steve Wagner, with the help of Tim and Josh Brahm, and some others who I likely haven't met. I don't know Steve [just Josh and, more casually, Tim], and that is probably good for the purposes of our commentary here, because if I felt the need to pull punches, I likely wouldn't be able to write much of anything.
If I were giving an academic response, it would meet a particular professional standard to be dispassionate and simply set in motion the lines of criticism of this article. But I should note the venue here matters a bit. This is more of an academic response, in terms of content, than most of what I post, but this is far from something I would submit to a serious ethics journal. I have no intention of writing such an article; as will become apparent, this article would need to be significantly stronger before a response would be publishable in such a venue. Further, I am not just presenting an academic critique, but also some [rather harsh] criticisms of the philosophical self-styling of the article which, generally, would not be made explicit in a mainstream philosophy publication.
I provisionally broke this criticism up into several sections, since there are a few rather significant chords of critique that jumped out at me on the first reading. There is, as always, some overlap between those problems. I've divided those sections by the order in which they occurred to me during that first reading, so you may note that the problems actually emerge a bit earlier. We'll call these lines (a) the naïve intuitionist line, (b) the legal intuitionist line, and (c) the general non sequitur attribution line. I don't generally like to gloss, especially on criticisms, and so this is gong to be a ponderously long post, even by my standards. Still, because of the disassembled nature of the article, which lends itself rather well to assessments of particular snippets of the article, I will work to keep each segment rather brief, as sort of a preface to each line of objection.
Without further shenanigan, let's get this show on the road.
the naïve intuitionist line (or: how to warn off ethical philosophers in the first page of an article)
Wagner begins the article by presenting a thought experiment in which a hypothetical woman is subjected to a behavioral psychology experiment in which she put in sole care of an infant for some arbitrary period of time.  Wagner notes that in such a case, he holds that the mother has a moral obligation to care for her child. In a case where the woman, Mary, abstains from helping the child and/or kills the child, Wagner writes, "I take it to be a basic moral intuition that what Mary did... in the cabin was seriously wrong. She has a moral obligation to feed the child."  So begins Wagner's case for the impermissibility of abortion.
Those who have training in ethics should grow immediately suspicious of what is going on here. Wagner has given us a case, given us his moral intuition, and asserted that this moral intuition is "basic" without some qualification of exactly what that is supposed to mean. For religious reasons, I strongly doubt Wagner is actually a moral intuitionist. However, the way that he presents the case, and the way that he continues to use intuitions throughout the article falls prey to a serious objection. I don't deny that ethical intuitions can be valuable,  but it is fairly easy to deny that they can be basic, either causally or inferentially, and that they can be sufficient grounding for the assertion of some sort of moral fact.
In the first case, it is clear that moral intuitions are not basic in any interesting causal sense. While there is some ongoing debate in moral psychology, it is uncontroversial that there is some set of psycho-physical causes for moral intuitions. Commonly attributed causes range from hormonal and neurophysiological factors,  as well as psychological features of individual affective character  and inferentially available beliefs.  Personally, I have a rather mean and energetic dog in the fight over how moral intuitions and judgments are formed; that's the subject of an article in process, though, and not really relevant here. All that we need here is an obvious observation about moral psychology, which is that moral intuitions are psycho-physically contingent and not primitive.
In the second case, a basic sampling of literature in moral philosophy shows that moral philosophers do not grant a privileged status to general intuitions.  The skepticism about intuitions is a long dead issue; very, very few take intuitions to be a sufficiently basic grounding for interesting moral claims and we see in the historical body of literature why. In short, it turns out that there are no good reasons to hold that moral intuitions, even by those with some form of training, are likely to be insightful since there are features that bear on such intuitions which are not causally related to the truth-conditions of the intuited belief, or on various truth-conditions of related propositions. It doesn't tell us at all whether the proposition that it is morally impermissible to kill a fetus, for example, is true. [Of course, Wagner feels the need to make lots of inferential moves here; we'll see where they fail along this line as we move through the critique.]
But presumably Wagner means that it is basic insofar as it acts as a basic starting point for the movement of his argument. The problem is that there are likely a fair number of folks who don't share the intuition. The black sheep for many of these "pro-life" advocates is their insensitivity to the libertarian position, or, rather, a particular variety of the libertarian position. This version of the libertarian position, let's call it L*, takes as primitive the notion that only positive acts can be morally impermissible. [Of course, this begs the question against the distinction between killing and letting die, but Wagner seems to acknowledge that there is such a distinction, however marginal.] Given that L* maintains this position, we can see that someone whose positions are derivative of L* or a set of psychophysical states which would instantiate L* would simply take Wagner intuition to be misguided in the "letting-die" cases.
I don't hold L*, personally, but I can note that there are people who do hold this position. I used to be among them, and I do still have some sympathies with the position. (We'll delve more into that in the following section.) Wagner might point out that it seems to generate some counter-intuitive cases to say that it is universally morally permissible to refuse to act. But given that L* informs moral intuitions, all Wagner is doing is voicing a faultless disagreement about features of our individual moral intuitions. 
The problem here is that Wagner is taking the intuition as basic, and so if we reject the intuition then we have sufficient grounds for rejecting the whole of the argument. But it turns out his condition is even worse that this. Moral intuitions don't have a special status, as many ethicists have shown. [See the above sampling of literature in theoretical ethics, or anyone cited in those papers; it is a really expansive literature.] When we assert that, for polemical reasons, an intuition ought to give any polemical force to the assertion of an ethical position, in order to account for cases where an individual actually disagrees, or a case where an individual might plausibly disagree, we have to be able to give some sort of moral reason. In this sense, even in the way in which Wagner takes his intuition to be basic, it cannot be. Wagner is obligated to give a moral reason for the truth of the proposition "What Mary did was wrong." [And now you see why I've disowned L*, because, on my view, abstaining from giving reasons seems to be objectionable.]
What is odd is that Wagner's is a position that Josh Brahm, and several of his students, have chalked up as a relativistic one in the past. In a response to me they articulate a version of relativism that seems dangerously close to Wagner's view.  After all, their understanding of normative ethical relativism, as they've presented it to me in public and in private, is that it begins with the move that the presentation of ethical intuitions and cultural norms are sufficient reasons for the truth [insofar as there can be truth] of an ethical proposition. Steve has some writing on relativism himself, so it is obvious that this isn't a consequence of his view that he has actively built it, but it seems a fairly obvious methodological pitfall. 
While it may be terribly uncharitable of me, I take this to be an instance of methodological laziness on Wagner's part in advancing the article. Presumably he is capable of giving moral reasons, apart from his intuitions, for the impermissibility of infant starvation, and he just chooses not to, likely for polemical reasons. Still, it may very well be that this piece of methodological laziness leaves the piece a complete mess. While it can, theoretically, be rectified, the presentation of a moral reason on Wagner's part would leave the piece open to some significant probing for the transitivity of the reason to the alternative thought experiments, and to the abortion case.
the legal intuitionist line (or: social reality and the insufficiency of psychological facts)
One of the few areas of the paper that seems to be on the right track is the move Wagner makes to talking about the legal obligations.  We can easily imagine an individual who holds that abortion is morally impermissible, but that there ought not to be a legal prohibition against it. In fact, I've found this to be a fairly common position among my pro-abortion-choice friends who have an evangelical upbringing. Wagner seems aware that absent the strong commitment to the legal impermissibility of abortion, the version of the "pro-life" position he and his colleagues are taking fails.
One knee-jerk reaction I've come across is that it ought to be the case that society instantiates a legal obligation for every identified moral obligation. Often, this position has been put before me by conservative Christians. These sorts of positions are where my unabashed libertarian and anti-fascist leanings can be found. I find these sorts of positions repulsive; as a result I've taken to referring to its proponents as "theo-fascists" or "crypto-fascists." I'm willing to defend that characterization, but we don't really need to here. Wagner may rest his case on such a move, tacitly, given the brevity of section [IIb] of the paper. In this section, Wagner writes:
"A parent's moral obligations, at least for feeding and sheltering their children, are so strong that we say there should also be laws forcing parents to do these things. If the moral obligations of a parent, yet temporary, then they must also be legal obligations. In other words, it should not be legal for a person in the de facto guardian position to neglect the feeding and sheltering of the child."
I won't accuse Wagner of jumping in on a theo-fascist position at this particular moment, since it does not seem strictly necessary for his position. Let's just say that he is taking a position that there are a set of obligations that are sufficiently important that they demand social reinforcement, they demand a legal institution, and "guardian" obligations fall under this category. Now, Wagner's point here seems to be that his de facto guardian situation seems not morally different from the general obligations of the parent; but this seems just obviously false.
Let's say, contra my exhibition in the preceding section, we grant Steve's use of moral intuitions. One can easily show that there is a plausible intuition to the effect that it is particularly morally egregious for a parent not to provide for their child, rather than for an unrelated stranger to provide for their child. Piggy-backing on the intuitionist move, we might note that the intuitive discrepancy in moral abhorrence between the two acts separates the moral value of the two acts in such a way that Wagner has to give an account of why it is that the de facto guardian case is still sufficiently strong to require a legal obligation. The asymmetry renders his move invalid.
But I don't get to make this move, because I've already rejected Steve's strong moral intuitionism above. So what do I do, here?
Well, I'm inclined to start by pointing out that Wagner has explicitly drawn his case out as a de facto guardian status; but the use of the technical term "de facto" in this way draws us into the contrast of the de jure obligation. A quick exegesis of the use of terminology, via my undergraduate constitutional studies professor, the three lawyers in my immediate family, and every legal dictionary ever, will note that de facto is used to designate cases where the status factually adheres, but is not legally [i.e. social institutionally] sanctioned. By stating that the guardian is solely a de facto guardian, Wagner is noting that there is no legal [i.e. de jure] status being imparted on the guardian.
To ward of a point of obvious incoherence, Wagner might say that he isn't arguing that the person is matter-of-factually a guardian by virtue of legal sanction; after all, there is no institution giving this guardian the legal status, and so a necessary condition for de jure status is not met.  Rather, he's arguing that the person should be considered a guardian on the presence of the articulated de facto [i.e. non-legal] obligation. This line might turn out to be plausible, but I suspect it won't if we pursue it seriously. Why? Because when we get into the practice of giving reasons, the reasons for presentation of legal sanction are not going to recognize the reasons that Wagner is giving for the moral obligation as relevant.
What are the reasons for the presentation of the legal obligation? Well, the generally accepted legal obligation seems to (from what I can tell; I'm a philosophy student and not a law student) stem primarily from the special status of the parents as biological relatives of the child and secondarily from the caretaker status given special provision by the courts.  We take this to note that the de facto guardian case gives us a general special case response to a legal obligation for the guardian without extending this out into a general obligation to aid strangers unilaterally in more typical cases.
"Ah ha!" Wagner might exclaim. "I've got you! The obligations are instantiated by the parental status, and so we see the impermissibility of abortion in the legal sanction!" But, of course, this move doesn't function, since we might note that a mother would be legally prohibited from starving her own child to death, but is (a) not prohibited from having an abortion, simply as a matter of fact, and (b) can draw attention back to the substantive bodily rights issue, on which the case presented by Wagner only gives us a very tenuous answer, as we see in the set of objections to his use of intuitions above. Also, I don't take the primary condition, the biological relation, to be sufficient for the existence of parental obligation; neither does the law, by all appearances, since there are conditions under which the parental obligation can be recognized as severed in spite of the biological condition being satisfied.
I don't think that Wagner provides a strong case at all that he can successfully parlay the obligation for a special obligation of a de facto guardian into something isomorphic with the legal obligations of a de jure parent. And I don't think that he can parlay the obligation of a de facto guardian in an injunction against abortion. There seems to be far to much in the way, not the least of which is that his use of "de jure" precludes direct translation into legal obligation.
the general non sequitur attribution line (or: when the conclusion follows from nothing at all)
One of the most destructive things that can be noted about a line of argument is that it is a non sequitur. Strictly speaking, any argument which commits a logical fallacy or is incomplete commits non sequitur. All that is meant is that the conclusions do not follow from the premises and the allotted rules of inference. We generally set the barometer a bit lower in the case of ethical arguments, since we don't expect that the argument will necessarily be deductive. All the considerations here are concerned with particular inferences advanced by Wagner. (I've left some of the instances in pieces attributed to contributors out of this discussion, since I don't necessarily have access to the entire content of the discussion.)
Let's be charitable to Wagner and stipulate intuitions as evidence and stipulate that the "This Looks a Whole Lot Like Pregnancy" case actually looks like pregnancy.  I'd argue that they're not sufficiently similar, and that we ought to simply introduce the matter-of-factual conditions of pregnancy instead of some lazy reconstruction of conditions we take to be like pregnancy.  But leave that aside and say that that Wagner's case is close enough. Wagner asserts:
"This scenario resembles the severity of burden of a typical pregnancy, but isn't it obvious that Mary still has a moral and legal obligation to feed the child? Yes. If not, how could any of these changes to the level of burden change her obligation? Remember, the alternative to her having the burden is that the child dies. In light of this reality, it is difficult to conceive of a way in which the burden could be adjusted to change her obligation to feed the child."
This is simply and obviously invalid. It does not follow that the consequences will not bear on our moral intuitions. Wagner simply takes it for granted (without explication or assertion as a premise for inferential use) that these changes are not sufficient to outweigh the death of the infant; there is no reason to hold this, though. Remember, the intuition is basically asserted, without reference to primitive causal factors. If it turns out that one of the psychological causal factors undergirding our intuitions in the first case is the perceived triviality of the act that the woman has to perform to sustain the child, then a change in the consequences will bear directly on the content of those intuitions.
It seems wrong to me to allow some other morally salient subject to die in order to prevent the suffering of a mosquito bite; I'd take this to be a trivial amount of suffering. However, it does not seem wrong to me to allow some other morally salient being to die in order to prevent myself from experiencing the pain of passing a kidney stone for a prolonged period of several months, or to prevent myself from being raped. These, it seems to me, are sufficient conditions which allow for the change in obligation, and there has to be some criterion of discrimination. We see that Wagner's inference is invalid because he does not provide such a criteria for maintaining the moral standing that is available for his inference. But clearly Wagner doesn't even believe this move, since he takes preventing death to be a sufficient reason for pregnancy termination. 
Perhaps Wagner's argument is that only when the suffering caused to the infant would be equal, or "same in kind," to the suffering prevented in the mother [i.e. death for one or the other] do we take the obligation not to stand, but I take this to trespass directly against both our intuitions and against direct moral principles.  But if this is Wagner's view, then he needs to state it explicitly in order to use it to infer the conclusion. Otherwise, the conclusion does not follow.
Let's take another case. There are several fairly serious non sequiturs in the article, and I think that an exhaustive account would have required simply focussing on them. I'll choose to present one more and allow the reader to pursue others.
Perhaps the most painful instance, because of its aggressive doubling-down on the importance of intuitions, is a passage after the discussion of J.J. Thomson's famous Violinist argument.  Wagner writes: 
"Imagine that Mary wakes up in the cabin and the baby is attached to her such that a short tube is protruding from Mary's stomach and entering the baby's stomach. Assume Mary has no formula but neither is she lactating. The only way for her to feed the baby is through the apparatus connecting them. The note tells her that she can remove the apparatus, but then the baby will not be able to eat, so it will starve to death. Does Mary have the moral or legal right to unhook? My intuitions are unchanged."
A bit of a jab here is necessary. Wagner's intuitions do not bear at all on whether or not someone has a legal right; this is a social fact of the kind discussed by Searle and others. There is a matter-of-factual assessment that can be given pre-theoretically about what will occur given the presentation of such a case, under a particular set of conditions. For Wagner to invoke his intuitions here is far more egregious than in the moral case, where there does not appear to be a ready pre-theoretical mode of assessment. But let's set that aside.
What Wagner has basically done here is to present a tailored version of Thomson's Violinist, where the violinist role is played by an infant, in order to off-set the disanalogies he discusses previously in the article, and assert that the withdrawal permissibility intuition is not met. Now, we will just presume that this is true for Steve. His intuitions are his; they belong to introspection. But what does he claim to derive from this as a conclusion? "Because the woman is a de facto guardian of a child, she should use her body to feed the child and can be expected by law to do so. She is obligated to stay pregnant."
I'm sorry, sir. But given that you make a point of setting apart the disanalogies in order to make your case, you do owe us a demonstration of the way in which you resolve these intuitions apart from simply the presentation of the case and forceful assertion of the conclusion. To do otherwise borders on literary (beyond just logical) non sequitur.
Now, to be fair to Steve, he might hold that some feature discussed in the disanalogies presented previously in the paper act as a sufficient reasons for the change in his moral intuitions; but it is, as in the previous case, not a stated inferential move, and so we see the failure of the argument to the conclusion. Further, he asserts explicitly that several of these disanalogies are irrelevant to his position, including the one discussed immediately prior to the rearticulation of the thought-experiment which primes his reassertion of his intuitions. The presentation of the argument assumes that the basic intuition is sufficient to count as some evidence for the conclusion, in spite of the fact that we have a previously acknowledged competing intuition in Thomson's experiment.
All that Wagner has shown in these cases is that there are competing intuitions between his intuitions about the cabin thought-experiment and many who advance the violinist thought experiment. He has asserted that these conflicting intuitions obtain even where the cases are sufficiently isomorphic in what appear to be all of the relevant respects; but he does not give resolution to the conflicting intuitions which would allow for the assertion of a strong conclusion.
some closing notes (or: before I go back to fantasizing about term papers)
I was warned that I would almost certainly not agree with any of the article by one of its contributors. I was told that I so whole-heartedly reject most of the premises on which the article would be based that I would probably be ideologically barred from accepting the conclusion even if I thought that it was a reasonably good work of moral philosophy. This assessment turned out to be more or less right.
Wagner succeeds in giving an articulation of a version of the intuitions surrounding bodily rights arguments and some of the objections to some articulations of bodily rights put forward by his friends, and showing how those objections accord with his intuitions under a certain set of crafted conditions. That is the extent of the success.
The paper is methodologically problematic. It begins and ends with the assertion of intuition as basic, a position which is fraught with difficulties so well known to the author that the dissonance is deafening for much of the technical content of the article. If I were writing a response in a scholarly journal (though such a response would necessitate the publication of the article in a scholarly journal prior to my submission, which seems unlikely) then I would numb myself through multiple readings and attempt to parse out the importance of a number of the technical claims about Thomson present in the body of the article and their relation to some conclusion about the moral content of abortion. Upon a second, third, and fourth reading of the article, I don't find any of the technical objections to Thomson compelling, and I don't find them weighing on my own intuition.
Insofar as the paper attempts to be a work in technical theoretical ethics, it fails. Obviously Wagner's point in constructing it in this intuition-heavy way is in part an attempt at lending rhetorical force; but it carries the consequences of what feels, at times, like an exercise in relativist allusion, where prior to post hoc rational justification the intuitions of the narrator are sovereign, the thing to which the truth-conditions of ethical propositions are, if not relativized, at least parameterized. This approach is simply ill-advised.
Most of this commentary was written in a stream of consciousness during a first bursts over the course of a day. I've proofed it, but it is likely to be a bit messy in terms of thought. That is, I suppose, one of the hazards of writing outside of the format of dispassionate philosophical critique.
I have access to all of the publications that I cite; unfortunately, for legal reasons I cannot distribute all of these texts. I've provided links that, in some cases, will take you to a full text and, in some cases, will take you to a site where you can purchase the texts. Otherwise, I've provided an academic citation.
 ibid pp. 2
 ibid pp. 3
 Haidt, Jonathan (2007) "The New Synthesis in Moral Psychology" Science 316.5827: 998-1002
 Singer, Peter (1972) "Moral Experts" Analysis 32.4: 115-117
 Wagner, Steve (2013) pp. 5
 For a more extensive discussion of how these moves function, see John Searle (1997) The Construction of Social Reality, which (as far as I'm concerned) is the most systematic approach in establishing a social ontology.
 There can be some argument here regarding readings in the details of the Mays-Twiggs case. The various cases of child severance from biological parents is taken on the basis of special extenuating circumstances; see also Kingsley v. Kingsley. I take this to be evidence supporting my claim that direct parentage is primary as a legal rationale.
 Wagner, Steve (2013) pp. 7
 Wagner, Steve (2013) pp. 7
 Wagner, Steve (2013) pp. 18