Making abortion illegal won't end abortion?  Of course it won't.  Gracious! What pro-lifer ever said or implied that it would?  What it would do is send a message that society does not tolerate infanticide.  It will also allow us to prosecute people who perform abortions, thus discouraging abortion.  

Making anything illegal does not stop the crime.  That is why we have criminals and always will.  It does, however send a message as to what is tolerated and not tolerated in a civil society.  It also allows us to prosecute people who break the just laws made by society thus discouraging the action.