Main claim: Abortion is immoral. In the Toulmin model, this is a claim of value.

Grounds: Here, the grounds are what is stated: supporting abortion is like supporting slavery, and everyone knows that slavery is immoral. Only those who were not aborted can support abortion, just as only those who were not slaves could support slavery.

Warrant: that that a fetus in a womb and a breathing human being who has been enslaved are analogous. The question being begged by the analogy, of course, is precisely the crux of the pro-life/pro-choice debates: whether a fetus (by definition unborn) is equal to a person and has the same rights as a person—the same rights as the woman carrying the fetus should have, the same rights as a victim of slavery should have, etc.

Type of Discourse: Epidictic + deliberative

Main logical appeal: Analogy btw supporting slavery and supporting abortion. Those whom the practice of both most directly effect, in other words, are precisely those who do not or cannot support it.

Pathos: The emotion evoked by the very mention of slavery would be shame, maybe anger–so linking pro-choice to pro-slavery evokes those same emotions toward the former.

enthymeme:

• major premise: slavery is immoral (because it asserts power over those who cannot contest it)
• minor premise: abortion also asserts power over those who cannot contest it
• conclusion: supporting abortion is immoral

Note that this argument is less about logic than about identification: You are one of those awful people who would have supported slavery, or you’re one of us.