The Free Will Defense for the problem of evil really relates only to Adam and Eve; because the Bible teaches that after the fall of the original couple, men's hearts incline towards evil. Man's nature post-fall is corrupt and is bent in the direction of doing evil. Man is totally depraved, meaning that left to himself, he will choose against God. So, according to historic Christianity, the only persons who were truly free were Adam and Eve. That means that the so-called Free Will Defense employed by Christian apologists really only applies to the original couple.
But were they even truly free? What precisely does it mean to have a truly free will? Does it mean that nothing is causing you to choose one option over another or does it mean that nothing is influencing you to choose one option over another? It seems that it must be the former, since it seems impossible for one to make any choice without being influenced by something. But is a will that is influenced, truly free?
I guess the question becomes how much influence is required before one is no longer culpable for his choice? In the criminal justice system, the defense of entrapment can be used by someone who believes that he was "improperly induced" into committing a crime. While this area of the law is complex and somewhat subjective (see Criminal Law , Thomas J. Gardner and Terry M. Anderson, [10th ed., 2009], 146-49 and Criminal Law, David C. Brody, James R. Acker, and Wayne A. Logan , 313-14), it is agreed that the defendant must have had a predisposition to commit the crime before he encountered the undercover officer in order to avoid the charge of entrapment. In other words, to prove the entrapment defense, you have to show that the crime is one that you would not have committed and that you had no predisposition to commit without the inducement of an undercover agent. Police cannot select random citizens to participate in organized sting operations in hopes of generating an arrest. There must be some compelling evidence that a specific individual has a propensity for committing such a crime.
So, in a sting operation, a person is put in circumstances which allows him to reveal his true nature or character, and predispositions. Thus, unless Adam was entrapped, he already had a predisposition to disobey God and eat the fruit. That would mean his nature was already corrupt before he fell (Jesus says that the desire to do something wrong is just as evil as the act itself, see Matt. 5:27-28). It seems therefore that God must have created Adam this way. God created him with a predisposition to commit evil. If Adam had no predispostion to commit the crime of eating the fruit and the snake convinced him to do so, that would be entrapment according to western jurisprudence.
Since one's will (i.e., what one chooses) is based on one's nature (i.e., what one is), it doesn't seem plausible to me that Adam had a truly free will. He was predisposed to disobey God from the moment he was created because he was created with such a nature (see next post).
So much for the Free Will Defense, as the fact is no one, not even the first couple (assuming they really existed) had a genuinely free will.