Environment: Again, the unborn are located in a different place, but how does location suddenly change you into a non-human? The only difference between a newborn baby, and an unborn baby is 8 inches of birth canal. How does moving 8 inches, suddenly change a blob of tissue into a human?
From a liberal standpoint, there could be the argument of symbiosis (I know, a stretch) and how if a parasite was attached (hang on) that you would want to remove said parasite (such as a leech) and not think twice about it.
Sadly, many women are duped (or more like delusional) that the cells growing in their womb is parasitic, and needs to be removed. If such women are convinced that they are removing something that isn't human, than they can assure their morality (how brutally ignorant it is.)
Last, Degree of Dependency: If viability is what makes one human, then everyone who is dependent on a pace maker, or some form of medication would be declared non-human. Perhaps you heard about the Siamese twins from Egypt who were in the news last year. One of the twins was physically dependent on the other twin; does this fact mean that one of the twins was not human? Dependency is not a criterion for being human.
The state of Florida has made it where people who are dependent on others for care - the infirm, the elderly, the handicapped, the ones with no voice - can be terminated according to judicial order. This process of dehumanizing the people who are the most vulnerable will lead to a destabilization of the society, such as what happened in the 1930's in Germany.
So, since the liberals won't realize the issue at hand, there has to be an infusion of people to maintain the current population status quo. Since 40 million of my peers have been aborted - and that constitutes actual abortions, not even counting the birth control pills, which is for another smokey back room there has to be adequate population paying into the system to maintain the current spending of the government. If you can't have it by natural population expandsion - children - then you import them. Importation is risky, because the imports don't necessarily assimilate into the society. Sometimes, they force the society to assimilate to them.
Best of luck, and remember to wear your Flame proof jammies when confronting irrational people.