Here is a bit of Catholic doctrine on Free Will [from new advent catholic encyclopedia] by Aquinas who expanded on the views of Augustine:
Augustine clearly teaches the freedom of the will against the Manichæeans, but insists on the necessity of grace, as a foundation of merit. He also emphasizes very strongly the absolute rule of God over men's wills by His omnipotence and omniscience--through the infinite store, as it were, of motives which He has had at His disposal from all eternity, and by the foreknowledge of those to which the will of each human being would freely consent. St. Augustine's teaching formed the basis of much of the later theology of the Church on these questions, though other writers have sought to soften the more rigorous portions of his doctrine. This they did especially in opposition to heretical authors, who exaggerated these features in the works of the great African Doctor and attempted to deduce from his principles a form of rigid predeterminism little differing from fatalism.
The teaching of St. Augustine is developed by St. Thomas Aquinas both in theology and philosophy. Will is rational appetite. Man necessarily desires beatitude, but he can freely choose between different forms of it. Free will is simply this elective power. Infinite Good is not visible to the intellect in this life. There are always some drawbacks and deficiencies in every good presented to us. None of them exhausts our intellectual capacity of conceiving the good. Consequently, in deliberate volition, not one of them completely satiates or irresistibly entices the will. In this capability of the intellect for conceiving the universal lies the root of our freedom. But God possesses an infallible knowledge of man's future actions. How is this prevision possible, if man's future acts are not necessary? God does not exist in time. The future and the past are alike ever present to the eternal mind as a man gazing down from a lofty mountain takes in at one momentary glance all the objects which can be apprehended only through a lengthy series of successive experiences by travellers along the winding road beneath, in somewhat similar fashion the intuitive vision of God apprehends simultaneously what is future to us with all it contains. Further, God's omnipotent providence exercises a complete and perfect control over all events that happen, or will happen, in the universe. How is this secured without infringement of man's freedom? Here is the problem which two distinguished schools in the Church--both claiming to represent the teaching, or at any rate the logical development of the teaching of St. Thomas--attempt to solve in different ways. The heresies of Luther and Calvin brought the issue to a finer point than it had reached in the time of Aquinas, consequently he had not formally dealt with it in its ultimate shape, and each of the two schools can cite texts from the works of the Angelic Doctor in which he appears to incline towards their particular view.
Regardless of God's omnipotence, I am not a puppet whose strings are being pulled by a tyrannical entity who is comanding me to sin. The choice has always been mine to do as I wish. Prayer helps in times of temptation and grace is freely given to help sustain me. Predestined thought is an excuse to behave as you wish without the consceince being excited.
What needs to be added here is the need for opposition for us to be able to make choices. Satan's plan, from the beginning was to redeem us without choice. The devil, still thinking his plan superior to God's, seeks to destroy the agency of man, binding when possible, us all with sin.
The way I see it the "big lie" in Genesis that was mouthed by the serpent is that we would not "surely die". The devil is determined to claim a victory to some small degree. The devil's victory is to claim us as his, which is called death. Death in the physical and spiritual sense is defined as separation from God who created us.
That the devil can separate some of us out to his victory, by binding us without choice, is a bitter yet limited victory over agency. Limited because we were given the "second estate" which is life in a mortal body, something the devil and his angels do not have.
Bump!