Mark Shea notes the zeal for abortion that dominates the Democrat party.
I'll just repeat here what I said in his combox;
Increasingly, it is abortion that is dividing the country politically. That is not going to change soon, and it shouldn't. It is not an issue on which one can very well choose not to have an opinion.
It's not surprising that battle lines have clarified along the abortion divide. It is the issue which most dramatically illustrates the differences between radical modernistic individualism and traditional social morality as the lens through which the Constitution is interpreted.
This is why playing to the mushy middle is more and more a fool's game, and why McCain's choice of Palin is - at least - a hopeful sign. The middle is shrinking. Fence-sitting on abortion is going to continue getting more difficult.