“In Opposition to the Law of God and Man”
The similarities of slavery and abortion are hard to ignore. They have been noted since within a decade of the Civil War itself. Dr. Joseph C Stone, a medical doctor and Union veteran called abortion a “violation of every natural sentiment, and, like slavery, in opposition to the laws of God and man.” 
Perhaps no controversy since slavery has divided the nation as abortion has for the past four decades. In a recent Pew poll, one fourth felt it was morally wrong, one fourth believed it was not a moral issue, and the remaining half sought middle ground.  On this volatile issue, America is once again “a house divided.”
Not Quite Human
Abortion rests at the center of another “cultural war.” It is a conflict of world-views. The focus of this “war,” like the debate over slavery, is the debate over human rights. The question for slavery was “is the black race to be considered human?” For abortion it is similar: “Can the unborn child be considered human?”
Using some of the same arguments as the proponents of slavery, pro-choice advocates have determined that the unborn is merely “potentially human.”  They have relegated the status of the baby to a non-existence. As with the three-fifth clause, the legal definition of “potential life” classifies the unborn baby as something less than fully human. Such terms as “fetus” and “cell mass” are used to emphasize this classification.
The arguments used in defense of abortion also mirror those for slavery. Constitutional right is the cornerstone of abortion defense. The “right to privacy” by Griswold v. Connecticut in 1965 provided the basis for this claim.  Rather than actually deny all rights to the unborn, Roe v. Wade determined the mother’s right to “privacy” superceded the baby’s right to “life”.
Property rights were a popular argument for slavery. Stephen Douglas argued that each person should have the right to choose for himself. Consider the following Douglas statements on slavery adapted to defend abortion:
It is no argument to say that abortion is an evil, and hence should not be tolerated. You must allow the people to decide for themselves whether it is a good or an evil. The pro-choice side both “denies the right of Congress to force the acceptance of abortion upon people unwilling to believe it is moral” and “denies the right of Congress to force the prohibition of abortion upon people unwilling to believe it is immoral.” The “great principle” is the right to choose, “the right of every person to judge for himself whether a thing is right or wrong, whether it would be good or evil for him to do it; and the right of free action, the right of free thought, the right of free judgment upon the question is dearer to every true American than any other under a free government. When that principle is recognized, you will have peace and harmony and fraternal feeling between all the States of this Union; until you do recognize that doctrine, there will be sectional warfare agitating and distracting the country. 
This argument fits well with the logic of contemporary abortion rights proponents.
Like the “scientific” argument that the Negro was inferior, pro-choice advocates argue from science that the unborn is not human. This point has drawn a great deal of controversy, revealing a diversity of opinion as to what actually defines human. In fact, one of the contentions pro-choice supporters had with the Roe decision was that it established a point of viability. They feared this would result in future restrictions as medical advances pushed this point earlier. 
Lack of intellect is often used to deny the humanity of the unborn. As with Lincoln and the opponents of slavery, the use of physical characteristics to deny rights is as objectionable to pro-life advocates. This opens the possibility for denying the rights of anyone less intelligent than the majority.
Another position is that while the “fetus” is both alive and human, it is not a person. Though admitting that it is human and even a “potential person”, these abortion defenders refuse to grant the right to life when it interferes with the right to “pursuit of happiness” of the mother.
 Marvin Olasky, Abortion Rites: A Social History of Abortion in America (Wheaton: Crossway, 1992), 128.
 Pew Research Center, “Pragmatic Americans Liberal and Conservative on Social Issues” 3 August 2006 [document – online] available from http://www.pewtrusts.org/ideas /ideas_item.cfm? content_item_id=3016&content_type_id=18; Internet; accessed 30 September 2006.
 Norman Geisler, Christian Ethics, (Grand Rapids: Baker, 1989), 135.
 Roe v. Wade, 410 U.S. 113 (U.S. Supreme 1973)
 D. J. Herda, Roe v. Wade: The Abortion Question (Hillside, N. J.: Enslow, 1994), 29-31.
 Benjamin D. Wiker, “A House Divided Against Itself Cannot Stand: The Looming War Over Abortion,” New Oxford Review, February 1999, Volume LXVI, Number 2. [journal – online] available from http://www.newoxfordreview.org /article.jsp?did=0299-wiker; Internet; accessed 27 September 2006.
 Herda, Roe v. Wade, 86-87.