You are missing the historical context. The ABA leadership officially adopted a Pro-Abortion position. Much of the general membership was outraged. The tactic used by the alienated Pro-Life membership in response to the Pro-Abortion leadership was to demand a full vote of all members. This was the "Pro-Life" position in this controversy. You need to understand this.
Miers' comments at the time, the one I've read, doesn't make that point at all. The objection to the the ABA taking a position was framed exclusively in terms of "this is too important an issue, and a leadership-only adoption on this divisive issue may marginalize the ABA."
In hindsight, Miers was likely correct. I would think that the ABA lost membership over the position taken.
And the only point I've been trying to make is that her poisition in advocating a full vote does not indicate which side whe would vote for. We just don't know, based on this. Bush cheerleaders marginailze their credibility by using this event as evidence that Miers is herself pro-life.