"it's reasonable to conclude that the Bible's authors never mention abortion because they weren't especially concerned about it."This is pretty weak reasoning. The bible makes no mention of eugenics, abortion, human cloning, euthanasia, or other questionable moral practices in human society, but that hasn't impeded Christians over the ages from coming to reasonable moral conclusions about such matters. In fact, such an "argument from silence" can be made only if you contend that
- the Bible should be taken as Christianity's sole comprehensive manual and explication of Christian morality and
- is indicative of early Christian thought, such that the perceived silence of the biblical text on any issue can be interpreted as a clear sign of ambivalence.
But neither of these points hold up to scrutiny.
It's clear by the author's argumentation that he is treating "the bible" per se as the sole comprehensive position on morality, by which we can gain insight into what Christians thought about a particular issue. But this is simply not the case. The earliest long-standing Christian traditions -- Catholic and Orthodox -- have from their inception typically revered multiple sources of authority. Catholics look to the Magisterium (or the teaching authority of the Church) as the formal interpretor of the word of God, as expounded by the Pope and the bishops in communion with him, traditionally expressed in conciliar creeds, canons and decrees (not to mention summaries of Christian doctrine and ethics like the Catechism). Orthodox Christians likewise make appeal to the dual authority of the Bible and Sacred Tradition.
Greeks and Romans employed abortion, together with contraception and infanticide, as methods of family planning (particularly against women). By contrast, the practice was shunned by Christians. The Didache ["Teaching of the Lord to the Gentiles (or Nations) by the Twelve Apostles"] -- dating from 70-100 AD -- explicitly prohibits abortion (2:2 "thou shalt not murder a child by abortion nor kill them when born". Lee does acknowledge that "there are later Christian writings that explicitly mention and forbid abortion, such as the Didache. But none of these documents made it into the canon of the Bible." However, the Didache was lost for centuries, was rediscovered in 1875 -- and despite is non-canonical status is still recognized due to its age and content as the earliest known Christian catechism outside the bible, and representative of the traditional thought of the early Christian Church.
Despite various theological speculations on when "ensoulment" occurred, Christian teachers such as Tertullian (c.160-240), Basil (c.329-379), Ambrose (c.340-397), John Chrysostom (347-407), Augustine of Hippo (354-430) down through Aquinas condemned the practice of intentionally procured abortion (much like the Hippocratic Oath of 5th century BC). Likewise, the sixth Christian ecumenical council in 678 AD equated procured abortion with murder.
Likewise, there is the Latin/Western tradition of natural law, which makes the moral case for various moral positions absent and independent of divine revelation. Adam Lee has some leverage here in his narrow focus on "The Christian Right", because insofar as such are by and large "Evangelical", Protestant Christianity typically does not lay claim to natural law.
Picking a fight with "Christian right" is an easy target -- so I can understand the obvious temptation for Mr. Lee as an atheist blogger. I do think it's a tad disingenuous for criticizing the use of "clobber verses" by his opponents, but indulging in the selfsame practice to bolster his own positions. However, should Mr. Lee wish to engage in some genuine debate on pro-life matters, he might consider some more heavyweight intellectual targets such as Christopher Kazcor (The Ethics of Abortion: Women's Rights, Human Life, and the Question of Justice) or Robert P. George and Christopher Tollefson (Embryo: A Defense of Human Life).
- Priests For Life have compiled an extensive list of various Fathers of the Church and their contemporaries on abortion, including pre-Christian sources, the Didache, citations from Early Councils as well as early Christian writings.
- For an Orthodox Christian treatment of the subject, see T.L. Frazier's The Early Church on Abortion. OrthodoxyToday.