We all know that slavery eventually became a fissiparous question that finally brought on a civil war. But what lingers in the mind is that perfectly good, kind, intelligent and well-read people accepted the institution, many without question, for years. If Thomas Jefferson could own slaves, where to find someone of higher sensibilities to rule that slave ownership was a grievous moral offense?
In other situations, with other perspectives, the question lingers. The civil rights debate of the 1960s put forward questions that demanded thoughtful moral consideration.
The Democratic Party attempted to prohibit thought on the question of abortion when at its convention in 1992 it declined to permit the Democratic governor of the state of Pennsylvania to give a speech -- because he opposed abortion, and the managers didn't want someone on stage who disturbed philosophical equanimity by raising the question of the unborn child.
The movement to eliminate thought on abortion has failed. Failed, because there is an assertive human point at issue, which cannot be denied consideration, any more than the question of slavery could forever be denied consideration.
Mitt Romney is hardly entitled to the Republican nomination just because he has confessed his doubts on the subject of abortion. But moral history is likely to bow its head to remark this sign of life of the moral conscience.