Let's discuss a bit about the nature of law, and more specifically, general piracy. When you decide to pirate something, you run a very slim chance of getting caught. Every time you run that risk however, you are accepting a potential consequence for your action, which in the case of piracy is usually a big, fat fine. Now, whether you intend to be accountable or don't intend to be accountable for your actions is a personal matter, but legally on the off chance that you get busted, you will be held accountable by the law.
A similar legal contract forms every time you have sex consensually. You are either intending to make a baby, or are using contraceptives. Contraceptives aren't perfect, leading to unwanted pregnancies, a consequence of casual sex. The legal contract that would exist in the case of abortion being illegal(except in certain circumstances) would require a woman to give birth. A similar contract occurs when a man has sex, requiring the man to provide for the child regardless of whether or not the man wants to. It's a legally binding principle designed to preserve morality and a decent quality of life for the child.
In the case that abortion is allowed, both parties are free to escape from their legal obligations. Let's look at the morality of abortion, however. What would you suggest differentiates a 2nd/3rd trimester fetus from a 1 minute old baby? The only difference is tangibility. You can see the baby. You can hold the baby. If the right to life is granted on the premise that babies are cute and you can hold them, how firm is that premise morally? Why does a fetus legally gain the right to life during the 3rd trimester in most states? It is a very frivolous way to give something the right to life. A concrete solution is required if we want to get anywhere with discussing the morality of abortion. We can't even really decide when something is alive, so how can we possibly decide when it is alright to terminate it's existence?
Also, for those of you suggesting that the reason abortion is moral is because the child will likely have a shit life, you are correct in assuming that the child's life will be shit but your reasoning is not. The solution to that is not to allow abortion for that reason, the solution to that is to fix what would lead to the child having a shit life.
That said, I have absolutely no sway one way or the other regarding abortion, and I couldn't really give a rat's ass about what's right or wrong as far as abortion goes. The flawed logic being used here is incredibly ugly and it needs to be pointed out however.