Let us just for a moment forget about that pesky little detail that the "Champion of Abortion," the plaintiff in the ground-breaking case, Roe v Wade, Jane Roe (aka Norma McCorvey), is now a Pro-Life Activist; and let us also for a moment forget about the scientific, moral, and philosophical arguments against abortion (Live Action has a great series making each of these arguments); and instead let us just focus on legal theory.
Granted, I have only a rudimentary legal education, but it is my ardent belief that the longer one stays in higher education, the stupider one becomes.
The Declaration of Independence and the Constitution guarantee us "Life, Liberty, and the Pursuit of Happiness/Property" Not "Property, Liberty, Life," or "Liberty, Life, Property," et cetera. The Founding Fathers ordered it "LIFE, Liberty, Happiness/Property" for a reason. It is in order of importance. Because you cannot have Happiness/Property unless you first have Liberty and you cannot have Liberty unless you first have LIFE. Therefore, by this standard, LIFE trumps liberty and property/happiness. For example, it makes some happy to kidnap other people. But this is illegal because it violates the kidnapee's liberty. Others feel it is within their liberty to kill people. But this is illegal and wrong because it violates the LIFE of those killed. In all matters, the issue of someone's LIFE is supposed to trump the exercise of another's liberty and happiness/property.
I am going to assume that many abortion advocates, and even many Pro-Lifers, have not actually read the Justices' opinions of Roe v Wade and its precedent (though I think you can hardly call it that since Blackmun released it mere hours before RvW), Doe v Bolton. Justice Blackmun's Majority Opinion is the single most erroneous and fallacious Supreme Court opinion I have ever had the displeasure of reading in my short study of the law. Give it a read sometime. You will wonder if Blackmun is really educated at all.
Anyway, Blackmun states right in the opinion that it is not the role of the Court to decide when life begins, nor CAN the Court decide when life begins. And then Blackmun goes right ahead and says that the Court has decided that life begins at viability, even though the Court does not know when that begins.
Yet, what Blackmun is completely disregarding in all of this is that in matters of uncertainty, it is the role of the law to proceed with the utmost caution. This is why the standard in American courts is "innocent until proven guilty beyond a reasonable doubt (or by the preponderance of evidence for civil suits)." Blackmun states that he is uncertain of when life begins, but that some hold that it is at the moment of conception; so if Blackmun were to follow the standard of the court that was set decades before his time, he would have ruled RvW in favor of the defendant. But he was an activist judge with an agenda who decided to completely ignore the standard of the court and throw out hundreds of years worth of common law (customs of the people) that had been built upon by many different nations and cultures, and now abortion is among the top causes of death in America (and the number one cause of death within the black community).
A+, America.
(Note: For further evidence of Blackmun's stupidity, look to the fact that in Blackmun's RvW opinion, he cited Griswold v Connecticut [the ground-breaking case that legalized contraceptives] for the "Right to Privacy" that is "found" in the Due Process Clause of the Fourteenth Amendment. Even though Justice Douglas, in his majority opinion for GvC, specifically states that the "Right to Privacy" can be found virtually everywhere in the Constitution BUT the Fourteenth Amendment's Due Process Clause.)