To begin, consider what the Calvinist doctrine of Total Inability teaches:
Calvinist, Erwin Lutzer, writes: “Thus the doctrine of total depravity leads directly to that of unconditional election--a dead man cannot respond to the gospel’s appeal.” (The Doctrines That Divide, p.181, emphasis mine)
Calvin adds: “Since the whole human race is blind and stubborn, those faults remain fixed in our nature until they are corrected by the grace of the Spirit, and that comes only from election. Two people may hear the same teaching together; yet one is willing to learn, and the other persists in his obstinacy. They do not differ in nature, but God illumines one and not the other. We are, indeed, made God’s children by faith--faith is for us the door and beginning of salvation; but there is something deeper with God. He does not begin to choose us after we believe, but by the gift of faith he seals the adoption that was hidden in our hearts and makes it manifest and sure. … Let us learn that God’s election is confirmed by faith in order that our minds may be turned to Christ as the pledge of election.” (Acts: Calvin, Crossway Classic Commentaries, p.229, emphasis mine)
Calvinist, James White, explains: “Outside of the miracle of divine grace changing a God-hater into a God-lover, no man would ever be saved.” (Debating Calvinism, p.64, emphasis mine)
White explains: “As one is in rebellion against the source of all true life, the result is called spiritual death--a death that only the miracle of regeneration, being ‘born again,’ can remedy.” (Debating Calvinism, p.69, emphasis mine)
So according to Calvinism, man is so utterly fallen, that for God to simply enable a person to receive Him, is completely insufficient, and therefore God must take the radical step of implanting an Irresistible Grace for anyone to receive Him. So the question then is this: If a person did truly repent, given their prior, fallen and depraved disposition, what might that indicate, if you are a Calvinist, concerning the type of grace that they had received? According to the Calvinist paradigm, it would have to be the aforementioned Irresistible Grace, otherwise they would never have been able to genuinely repent in the first place. So if a person does truly repent, then it must be indicative of an irresistible grace, and if an irresistible grace, it must be indicative of a Special Election. So that raises an interesting point. What about those who have truly repented and received Christ, but yet have not accepted Calvinism, and in fact, have completely rejected it as a False Teaching? What you are about to see, is that some Calvinists will deny that these had ever truly repented, and must still remain in their unregenerate, depraved state:
Calvinist, Matthew McMahon, writes: “When I was 21, I had a form of godliness but I denied its power. I had a system of doctrine which denied Jesus as the only Sovereign and Lord. Yet, God in His mercy forgave that heinous sin of wrong belief. He allowed the scales to fall from my eyes. He allowed me, if you will, to be ‘born again, again.’ My mind has been renewed and my life transformed by these doctrines of grace. It is absolutely true what Spurgeon said, that Calvinism is nothing other than a nickname for Biblical Christianity. And until a person understands these doctrines, his walk with God will be a superficial walk.” (Why I am a Calvinist, emphasis mine) Sovereign Grace Church asks: “Must a person believe ‘the doctrine of election’ to be a Christian? The answer is yes, as surely as one must believe and accept God's grace to be a Christian. To cut election away from grace is to have ‘grace’ which is no grace. To cut election away from the gospel is to have a ‘gospel’ that is no gospel, for a gospel without grace is another gospel from the Biblical message (Galatians 1:6-10).” (http://www.sgc-gettysburg.org/writings/argument2.asp, emphasis mine)
Calvinist, James White, writes: “This is not to say that there are not unregenerate, unsaved men who understand the outlines of Christian theology, for example, or the claims of the Christian faith. What it does mean is that there is no unregenerate man who spiritually accepts, understands, and knows the things of God.” (Debating Calvinism, p.69, emphasis mine)
Casting aside a mere understanding of theology, is there any unregenerate person who ever repented, professed Christ and believed in their heart that Jesus Christ was Lord? The Calvinist answer has to be no. Why? Because they are supposed to be so enslaved to the depravity of sin that they cannot repent. Put aside the ability to live a perfectly holy life, Calvinism teaches that the unregenerate are so enslaved that they cannot even make one true act of repentance, unless they are made preemptively Born Again, and therefore Calvinist hard-liners must ultimately conclude that Arminians hate God, while in contrast, Calvinists love God, and that Arminians have never repented while Calvinists have.
Nevertheless, the question remains: Which it is that the Calvinist hard-liners will give up: Total Inability or confess that professing non-Calvinist Christian believers are in Christ? John Calvin’s answer was something called Temporal Grace:
John Calvin explains: “Let no one think that those [who] fall away...were of the predestined, called according to the purpose and truly sons of the promise. For those who appear to live piously may be called sons of God; but since they will eventually live impiously and die in that impiety, God does call them sons in His foreknowledge. There are sons of God who do not yet appear so to us, but now do so to God; and there are those who, on account of some arrogated or temporal grace, are called so by us, but are not so to God.” (Concerning the Eternal Predestination of God, p.66, emphasis mine)
However, this creates another dilemma for the Calvinist, which is that Temporal Grace would rob even the Calvinist of any real security. Ultimately, Calvinism then would become a works-based religion in order to prove that they do not possess a mere, Temporal Grace, and never knowing when such temporary grace would be withdrawn. The moment any Calvinist slips, they must indeed ponder, “Is it just Temporal Grace that I’ve been given, and now to just slip back into the mire of Total Depravity and perish according to the predestined will of God?” Calvinists, pick your poison.