As it happens, abortion as a political issue has never made too much sense to me. It seems that in order to be properly consistent with their views, the left and right should switch stances on this issue. The left, more often than not is the champion of the downtrodden, including foreigners, the underprivileged and sometimes animals, why unborn fetuses were added to this list is mysterious to me. The right also likes to think of itself as both coldly rational and as a group with distinct respect for personal liberty and privacy, but strangely enough, they dawn their statist bleeding hearts when talking about fetuses. Of course politics is an ever-long monument to human contradictions and inconsistencies, so this is only an inceptionary note, not a statement of topic.
Obviously my goal here is looking at abortion in social morality; that is how to look at it if we assume the goal of our laws and our system of justice is to maintain an orderly society for all of its participants. Now I take issue with the emotinalized statement that "abortion is murder." This is not the kind of anal (but important) distinction as that between killing and slaying, but it's worth bringing up why precisely we prohibit the antisocial act of murder.
First, it must be said why murder is conceived of individually and evolutionarily as such a heinous and damaging social act. A murder takes from society far more than a human life, even if we do not assume that that is something of innate value. Murder ruptures the social structure of society by eliminating a member with possibly numerous dependents and connections. All of the social investment that had been placed into this murdered patient in forms of education, amicable bonds, alliances, or personal trust are forfeit and any resources put into these factors wasted. This murder causes discontentment amongst those member of society who relied or had come to live their lives in companionship with this victim. At that, other, even unrelated members of society must put themselves at guard for the prospect of murder coming again, a further waste in the form of perhaps unnecessary precaution. And then, the miserable final touch is the rational incentive of the bereaved family to obtain revenge to prevent further death, an action which more often than not would result in the mutual eruption of vendettas causing a continuous trail of the same type of social loss and disruption.
This is what is entailed by the word murder, and if not, it is the pattern of events that at its core represents the reason murder is considered an antisocial and a punishable act. So one now must consider which of these negative consequences come about from the act of the abortion of a fetus; for it seems to me that none do. No social bonds or alliances are forfeit nor is any social investment made useless, the fetus has not incurred any social attention or awareness to be destroyed upon its silent termination. Abortion as a private matter could only disturb one member of society, that being the agent woman involved. It is possible that the act of abortion could cause an emotional uneasiness in the potential mother, particularly if she had been repetitively told that such an act would categorize her as a murderer. But that again is simply an aspect of social perception, and does not seem to be widespread.
Therefore if we say that society is an institution that supports social behaviors and punishes behaviors that ripple into damaging other members of one's community, which it is nearly by nature, there seems to be no self-evident reason to qualify the termination of a fetus as an act of murder. There is no way that abortion can be reasonably compared to the social destruction entailed by murder.
The idea that it could or should be is similar to a moral overgeneralization. There is quite an evolutionary incentive for an innate predisposition against murder to arise in a society which aptly punishes it. This moral sense, although based on initial practicality, can be reutilized in a generalizing sense to indue a general disgust with killings isomorphically similar to the murder of a human which is the cause of such social damage. From this, quite tangibly, we can cultivate moral senses for fetuses, animals and other things outside of the social structure.
Now of course, it may be that human fetuses will or already have fallen into man's "Expanding Circle" of empathy in some ideological communities. If our culture places emotional and moral value so extreme on the fetus, it would mean that abortion would cause social damage to those so enwrapped in empathy for them. This might be grounds for a curbing of abortion, but as it happens, even communities which stand ideologically strong against the ethical justifiability of abortion, Evangelical Christians for example, ironically some of the highest tallies of pregnancy terminations are maintained, indicating that any social emphasis placed on unborn humans is insufficient to supersede the benefits of abortion even for themselves. It should be a fact of considerable joyousness for them, however that since the expressed legality of first-trimester abortions in Roe v. Wade, the tallies of abortion have considerably fell, especially in pro-choice communities as it happens.