Making God A Liar?

This was a question that came into SEA, and I thought it would be a good idea to share my thoughts on the subject more publicly. The question is as follows:

1. If human beings have libertarian free will, it is within their power to make God a liar.
   
2. It is not within their power to make God a liar.
   
3. Therefore, human beings do not have free will.

The troublesome premise is probably the first one, so I'll explain what I mean. Imagine a scenario where God makes a promise to one person which requires for its fulfillment the cooperation of another person who is free in the libertarian sense (I take freedom in the libertarian sense to mean that in any circumstance, a person's choice is free if he has two options to choose from [acting or refraining from acting, for example] and his choice isn't coerced, and so on).

Let's say God promises to the first person S that he will have a child with the second person S* before the end of the year. The fulfillment of this promise clearly would involve S*'s cooperation: she could just turn S down every night and never have the child. But then God's promise goes unfulfilled and God is a liar--which is not possible. Therefore, S* cannot have free will.

The person then went on to list several possible responses, which to me shows that the person was trying to be fair, and I respect that. Some of them I'll mention, but what follows are my own thoughts:

1. God not being a liar is a relational and moral quality, not an essential one. This is a confusion of categories. God is not a liar because he would not promise something that He would not fulfill. Thus, the initial premise is based upon a situation that God Himself would never enter into, for He would not promise that which He would not come through on.
   
   For instance, if I promise my nephew that my wife would let him have ice cream, and then she doesn't, she did not make me a liar. I made myself a liar by promising something which is beyond my own will. Therefore, it was not caused by the power of my own wife, but from my own hubris in this case. It is my own relational failing, something which God would never
   
   
2. Due to God's omniscience, God knows every event which will transpire. God's sovereignty would mean that the error that I made in the above example an impossibility anyway since He would know whether or not she would let him have ice cream.
   
   This is one of the possible objections that the original author mentioned, and gave a possible response to it:
   

   Even if God knows what S* will do in certain circumstances (however that works), it is still within her power to make God a liar. Imagine if, on the last night before the New Year, God knows that she will not turn down S and will get pregnant--in order for her choice to be free in the libertarian sense I outlined above, it still has to be within her power, all things being the same, to deny S. Therefore, it is still within her power, even if it were never actualized, to make God a liar. But God cannot be a liar. So S* cannot have free will.

   However, I don't think this response is valid. This is because of the points 1 and 6 here, but it is also because you cannot claim that someone has the power to accomplish something that they'll never be able to accomplish. That's not really having the power. Making someone a liar is, by nature, an opportunistic ability and, as such, if the opportunity will never exist, then there really is not power there to begin with.
   
   
3. The vast majority of God's promises made in Scripture are conditional. This is important in connection to the above point. God always maintains His integrity by only promising contingent things in light of the appropriate conditions for those things. The only times His promises are unconditional is when the event is predestined.
   
   
4. God is sovereign which means that He is in control of the situations around a person. If He ordains that a particular end will come to pass, He has the authority and the means to arrange it to come to pass through a variety of circumstances that He can adjust (in His eternal plan of course) in the event of people resisting His will.
   
   
5. The person is working with a false sense of free will. Free will does not mean that the will makes decisions perfectly autonomously all the time. Only that the capacity to make autonomous decisions exists, is frequent, and God has decreed that certain events, such as one's personal salvation, shall be contingent upon such a decision. But God still possesses the power and the right to overcome that free will if He deems it necessary to achieve that which He has decreed would happen, such as the eventual hardening of Pharaoh's heart, or the tortuous spirit sent to Saul. Therefore, there is nothing wrong with God arranging things to get a women pregnant if it is indeed something important enough that God would make such a promise (though I personally would question the morality of it in that particular case). However, I would hold that God rarely overrides the will and when He does, it is for something far greater than making sure someone doesn't make Him a liar.
   
   
6. The issue of free will is not really an issue of power. The person is casting the notion of free will into Calvinist paradigms. Free will is not a power that human beings naturally possess, but a provision given by God for His own purposes. That purpose, as Arminians understand it, is to create real relationships with His people. It is false to believe that God doesn't force people to do things because He can't, as if free will possesses some kind of quality that surpasses the might of God. He doesn't do it because He doesn't want to. His desire for us is as a father to children and as such He wants us to make our own choices, grow, and mature. Free will exists because of His father's heart.