Once again, it looks like "what ifs" are being thrown in the way of saying what abortion is. If we look at murders as we already know and deal with them, we all know that extenuating circumstances affect the legal process, just as happens with other crimes.
So if there are a few--and I emphasize few--extenuating circumstances that might affect the sentencing meted out to someone charged with the murder of an unborn infant, its still a homicide! But, of course, that is not so if the act is never to be considered be a crime in the first place under any circumstances.
For me there are multiple issues here, and each one operates on a different level.
Personally, I struggle to consider abortion to be morally justified. Whatever Scripture might say, whatever the law might say, I struggle with the idea that a pregnancy (at least a pregnancy developed enough for the mother to know she is pregnant) is anything other than a human being. On that basis I would be opposed to abortion and would not seek an abortion for my wife. That doesn't give me any right to demand that anyone else take, or refrain from taking, any specific action.
Next up is the question of what Scripture says. If one can make a compelling appeal to Scripture that demonstrates abortion is unacceptable in God's eyes, only then can it be expected that an argument should have any standing among other Christians. Even then, there is still scope for other Christians to take a different stance backed by their own appeals to Scripture (just as is the case for everything from drinking to dancing to homosexuality). A valid and even solid appeal to Scripture still doesn't give us the right to demand that those who do not follow Jesus pay any attention to us.
To change the law at a national level it would have to be legally recognised that the bundle of cells is in fact a human being in its own right. This requires medical evidence rather than appeals to this or that holy book. And this is how it should be - as soon as we start down the road of expecting elements of our own faith to be enshrined in law we leave things wide open for other faiths to make similar demands.
If the law were to be changed to make abortion illegal the associated question would be what, if any, circumstances would have to exist to make it permissible and whether a definition of such circumstances could be misused. As far as I can see there is no combination of circumstances that would allow for an abortion under the very few extenuating circumstances under which few people could possibly object, that couldn't be abused by a friendly doctor or a false claim.