The discussion of the continuum is based on an illogic that describing one criteria regarding a zygotic process should not be valid because the same criteron can be found true in -- for example -- a geriatric person with Parkinson's. This is a meretricious argument.
But I am not trying to get people here to accept my view of how the conception to birth cycle operates or how it should be viewed.
What I AM in favor of is defining the boundaries of moral imperatives, no matter how strongly felt. This is a difficult principle to parse, indeed. A man who believes that all abortion is murder can easily see that he must stop at nothing to prevent this from happening, even if it means burning down clinics. From a moral perspective he is to be forgiven, because he is in the grip of an undeniable moral imperative. If he trades off the life of a practicing doctor in doing so, I suppose the rationale is that he has saved hundreds of unborns, and therefore done the greatest good for future humanity.
This moral imperative business is pretty tricky -- it is the core justification for Bush's signatures on marching orders that have brought about the death of almost 4,000 Americans (more than perished on 9-11), and ruined the minds and lives of many thousands of others, and millions of Iraqis. He had a little chat with the Almighty before signing those orders.
And the impulse to impose these moral imperatives either through interference with outhers' lives, or through indirect interference by lawmaking, is one of the screwiest aspects of our culture. What is in theory is the process of winnowing out the greatest good for the nation becomes a battle of interference engines and their supporters.
My personal opinion is that the way to generate moral boundaries on abortion or any other issue is not to appeal to the machinery of law, but to focus on the art of disseminating your ideas, and let the market of thought buy it or not. THis puts you on your mettle and makes the seller of the meme responsible for cleaving to comprehensibility. It is very clear that law making does nothave this burden.
Using the law to do it for you is just laziness. Of course, there are an awful lot of lazy guys out there! :D