Despite decades after Roe v Wade, abortion remains a central issue in American polticics. Why, given that the other issues of the age have been long since buried, does this continue to pose not only a contentious problem, but a rallying cry to the Christian right? There are some that believe that this debate lives on because it could never reach its natural conclusion through civil discourse; however the Loving case ended debate on interracial marriage in a similar abrupt and activist manner, and the national fabric has adopted it thoroughly. Why not so with Roe?
I suspect we continue to argue about Roe, and about abortion, because we have miscontextualized the debate as a womens' issue.
Perhaps in 1973, the issue was properly one of womens' rights to control their own bodies versus a statist/patriarchal desire to control them. I don't think that's the case today. I think the country has more or less accepted a woman's legal right to do as she pleases with her own body. Certainly those opposed to abortion do not phrase their arguments as issues of reproduction or women's rights.
We can get into deconstructionism here, and read "control of women's bodies" and "control of sex/reproduction" as the implicit subtext used when an overt appeal is clearly socially unacceptable. This is a traditional liberal interpretation of conservative arguments, and it is not always erronious. The "issue" of gay marriage, for example, has virtually nothing to do with marriage and everything to do with a fear gay people as an element of the American social fabric. In this case, however, let us entertain the notion that right in this country is honest about its motives: the belief that life begins at conception.
At a certain point (traditionally, birth), a fetus becomes considered a person under the law, entitled to protection. The abortion debate remains intense and confused because it touches on a key issue for the twenty first century: what makes us human?
From abortion, to stem cells and cloning, to the Schaivo case, a large subset of the "culture of life" issues aren't really about life so much as humanity. What grants us that unique quality which makes humans legal and moral entities entitled to constitutional protection-- and, just as importantly, why? This question is only going to grow more pressing as biotech evolves, and the liberal side of the argument has yet to articulate a clear and coherent doctrine. The conservative/religious side of the argument does: life begins at conception because that's when the soul enters the body.
Obviously, this should be unacceptable to us because it puts the federal government in the position of applying an essentially mystic and definitionally untestible quality to determine who has rights. But what alternative do we have? Can anyone articulate a better standard for this issue?
Intuitively, I tend to gravitate towards a first-trimester cutoff based on brain activity, but this is a hopelessly murky standard utterly bereft of the clarity that a conception standard offers, and it acts only as a test rather than offering a rationale for it. Until we can articulate a different standard for WHY we should be protected, we will be forever hindered in attempting to reach a national consensus on abortion.
Digression:
We talk about rape and incest as though they ought to be exceptions; this sort of logic proceeds from the understanding of sex as Sinful-- as though the lack of volition nullifying the sin of sexuality and thus the need for pregnancy as "punishment". It only makes sense from the frame of abortion as a womans liberation issue. If the morality of abortion stems not from the actions of the parent but from the need to protect an unborn person, then it is both incoherent and hypocritical to regard these as valid "special cases". They (unlike "the life and health of the mother") retain no moral bearing on the central issue.