Of course you think you are right! Why bother to put your points forward if you don't think you are right unless you are playing devil's advocate and I don't think you are. I was talking about legal or illegal not right or wrong. Murder is the unlawful taking of life therefore abortion is not murder according to law. You may feel the law is wrong and that it is murder but the fact is that it isn't at the moment. So it's not murder - by the way talking down to me doesn't make you look smart it just sounds like you are ranting.
So we have agreed that abortion is legal. Murder is the unlawful taking of life therefore even if a foetus is a human life as you propose, taking it isn't murder. I agree that doesn't mean it is right. I presume you would agree that taking the life of a Doctor carrying out his lawful business is murder too?
Assuming the poll is accurate 51% is a simple majority I agree, let's assume that this has been the case for a long while too (although I don't know whether it has or not). It leaves a significant minority opinion. The law is not there simply to enforce the majority view though as I am sure you would agree particularly on such personal matters. To be more precise then - there is not a significant majority in favour of banning abortion. If there was it would happen. Why isn't there if it is so clear that it is wrong?
Whether a person believes that abortion is acceptable (at any point of development) is a moral decision at the moment. The law effectively allows people to make their own decisions on the matter. If people are religious their decision may be informed by that. If they aren't they may still take a moral view or they may not. Personally I think this is a sensible position unless you think a return to back-street abortions is acceptable.
Your analogy with Income Tax is an interesting one. If people don't like the levels of taxation they can replace politicians with those who advocate lower taxes. Sometimes they do just that. At the end of the day though the electorate know that taxes are necessary, it is simply a question of the level of taxation and how the money is spent. Not really the same issue it is?