Argh someone up there lit the fuse.... Sorry.
The issue of abortion is intrinsically intertwined with religion, which is what makes it so contentious.
I guess that the belief held by theists is that the 'soul' is 'created' at the moment of fertilisation, and that termination of the foetus at any point from then on is murder. Personally, as someone who doesn't have faith, I obviously don't believe we have souls. So therefore when you terminate a foetus that has yet to develop feeling or become sentient, you aren't destroying something that has become a person yet. For that reason, I couldn't class abortion as murder.
As far as the Law is concerned, it is a real conundrum, because murder is killing another human, and lawyers/lawmakers have to thus define what exactly it is to be human, and when we become human. Where to make that distinction is based upon opinion alone, depending on your religious belief. However what we must be clear upon, is that in pluralistic societies the law cannot get itself involved with religion. It must be something that is wholly independent from mere belief. So that is why as the situation stands, abortion cannot be legally classed as murder.
Nobody ever suggests that a woman having her period amounts to murder - that would be ludicrous. So are we to infer the anti-abortionists' suggestion is that from the second the egg is fertilised, if it is destroyed intentionally, it amounts to murder? That would then make miscarriages manslaughter! People calling abortion murder helps nobody, it seems to be little more than an emotive argument.
So...uh...yeah, oppose abortion if you like, just please don't call it murder.