The slippery slope argument is a fallacy they said.

In spite of the oxymoron in the expression, we propose to call this practice ‘after-birth abortion’, rather than ‘infanticide’, to emphasise that the moral status of the individual killed is comparable with that of a fetus (on which ‘abortions’ in the traditional sense are performed) rather than to that of a child. Therefore, we claim that killing a newborn could be ethically permissible in all the circumstances where abortion would be. Such circumstances include cases where the newborn has the potential to have an (at least) acceptable life, but the well-being of the family is at risk. Accordingly, a second terminological specification is that we call such
a practice ‘after-birth abortion’ rather than ‘euthanasia’ because the best interest of the one who dies is not necessarily the primary criterion for the choice, contrary to what happens in the case of euthanasia. (2) There are two reasons which, taken together, justify this claim:

1. The moral status of an infant is equivalent to that of a fetus, that is, neither can be considered a ‘person’ in a morally relevant sense.
2. It is not possible to damage a newborn by preventing her from developing the potentiality to become a person in the morally relevant sense.

I remember in high-school debate, making the argument that there is a slippery slope in the reasoning of those in support of late-term abortion. I specifically argued that since the justifications used in favor of abortion could just as easily be applied to newborn infants with unfavorable traits, that the justifications in favor of abortion should be discarded (I didn’t even know what reductio ad absurdum meant).

I came to realize, so I thought, that my argument was likely mistaken. Even though warrior cultures in the past discarded babies with unfavorable traits, that as a global civilization we were past that and my argument was unrealistic. Twelve years later and it turns out I was right, a peer-reviewed ethics journal used the exact argument I proposed was coming. I mean, down to the premises and conclusion, it is basically the same. I wish I were more organized in high-school and had written these things down rather than just having ad-hoc discussions with people at competitions (btw, this was never a thesis we debated in competition).

I’m not saying I was prescient. I wasn’t. I’m saying that most sensible people saw the analog between the two ideas. They often knew that it had to be in the minds of those who supported abortion rights. Such people, in a misguided sense of rhetorical good-faith or dialectical charity simply, thought it was unacceptable to actually impute such ideas to others.

I’m starting to wonder (though I can’t be right about this) if every time you tell somebody that their idea sounds like it supports (X) and they protest with dozens of qualifications, the person really does support (X). If the person simply says, “No, I don’t support (X),” then they probably don’t. Remember folks, we may have technology, good movies, and lots of awesome micro-brewed beer, but we live in a world wherein infanticide is being renamed and viewed favorably amongst academics.