Abortion in America is a fifty year old political story. The closer the child gets to birth, the more voters dislike the idea of abortion itself or anyone associated with the procedure. The closer the child gets to conception, however, the more those same voters become comfortable with the much more ambiguous idea of "terminating a pregnancy."
When the abortion political debate is moving toward the former outcome, it becomes a winning issue for the pro-life Republicans (and their more reluctant Republican colleagues). If on the other hand, the debate begins to move toward the latter outcome (i.e. conception), it then becomes a winning issue for pro-choice Democrats (and their deeply closeted pro-life Democratic colleagues).
The above description is not advocating either outcome. Instead, it is an attempt to describe how politicians see the issue when talking to their constituents. Guess wrong and it may cost someone their seat in high office, but that's life in a democratic republic.
