Last week the nation passed the 41st anniversary of Roe v. Wade, the Supreme Court decision that nationalized conditional abortion rights. Despite the hope of some that Roe represented a final settlement, abortion continues to make its way into the news in a variety of forms, and the issue seems more intractable than ever.

Recently, National Journal columnist Ronald Brownstein, commemorating the 150th anniversary of Abraham Lincoln’s Gettysburg Address, wrote, “Today we face no disagreement as morally grave, or as resistant to compromise, as slavery.” Well, pro-life advocates would beg to differ, seeing in abortion an issue that is precisely as morally grave as slavery.

Many readers probably find that statement to be ludicrous. So, while I recognize there are multiple sides to every issue, I’d like to explain this intensity of belief by highlighting the connections between what we could call the matching pro-choice perspectives.

The central question in the infamous Dred Scott Supreme Court decision was whether the slave was primarily and essentially a human person, and thus entitled to the personal liberty guaranteed by the Constitution. The central question in Roe v. Wade was whether the fetus is a person within the meaning of the Fourteenth Amendment.

The Supreme Court’s position in Dred Scott was that the slave was not a person within the meaning of the Fifth Amendment (which protects us from having our liberty deprived without being convicted of a crime), arguing that blacks, whether slave or free, were “beings of an inferior order… and so far inferior that they had no rights which the white man was bound to respect.” The Supreme Court’s position in Roe was that the unborn are not persons within the meaning of the Fourteenth Amendment’s due process clause, arguing that “we need not resolve the difficult question of when life begins,” while at the same time apparently resolving that question by asserting that the unborn are “potential life” and “prenatal life.”

Dred Scott declared slavery legal and constitutional; Roe declared abortion legal and constitutional. The first said blacks may be human, but they were not persons in a constitutional sense; the second said the unborn may be human, but they are not persons in the constitutional sense. In both cases, blacks and the unborn do not merit legal protection.

Broadening the scope beyond the confines of Supreme Court jurisprudence, proponents of slavery said slaves were the property of their owners (masters); proponents of abortion rights said the unborn are the property of their owners (mothers). If you think that’s an inflammatory statement, consider some of the rhetoric from the abortion rights side: “keep your rosaries off our ovaries,” “our bodies, our choice,” and the view that “fetal tissue” is simply “part of a woman’s body.”

One said the right to property trumped the right to liberty; the other said the right to personal liberty trumps the right to life. Alternatively, the right to personal liberty for one person (slave owner or pregnant woman) supersedes the right to personal liberty for another (slave or unborn).

One defended slavery using the argument that abolitionists should not impose their morality on the rest of the nation; the other defended abortion using the argument that those who support the right to life of the unborn should not impose their morality on the rest of the nation. Put simply, one side in both debates is “pro-choice,” and the other is not.

Finally, one led to the perverse conclusion that slaves were partially persons in SOME circumstances (they could be held responsible for their actions under the law) but not in others (they were also regarded as property and as extensions of their masters’ will); the other led to the perverse conclusion that the unborn ought to be protected in SOME circumstances (we have laws that punish the killing of the fetus in an unlawful way, such as assault or drunk driving), but not in others (it’s OK to dispatch the fetus if you are the mother).

These are the parallels some people see, and to the extent that we agree that slavery was a moral outrage, pro-life advocates believe the same thing when they see 50-plus million lives were lost to abortion over the last 41 years. For them, it’s an injustice that is as morally grave as any you can imagine. That’s why the issue doesn’t go away.

David Crockett, political science professor.