I define the dead state of our spirit as sinners and moral beings as being totally unwilling to sin, not totally unable to sin. We, as believers, are to be dead indeed unto sin. That does not mean we are unable to sin, but rather that we are to be totally unwilling to sin.
If we are moral beings the will must be free to choose. If the will in all sincerity cannot choose anything other than it does under the very same set of circumstances, the individual is no longer a moral being accountable to moral law.
And that is why there is such confusion among Calvinism, as they take Scripture out of context and redefine texts.
The word "death" or "dead" always means "separation" in the Bible. You clearly have a wrong concept of death which greatly affects your theology.
What happens at the "Second Death?" It is eternal separation forever, a final sentencing of all the lost in the lake of fire.
What is physical death? It is the separation of the spirit from the body.
Scripture?
James 2:26 For as
the body without the spirit is dead, so faith without works is dead also.
--When the body is separated from the spirit death occurs. Death is separation.
Notice how it is sin that separates one from God.
Isaiah 59:2 But
your iniquities have separated between you and your God, and your sins have hid his face from you, that he will not hear.
Ephesians 2:1 And you did he make alive, when ye were dead through your trespasses and sins,
--Thus there is spiritual death. Sin causes separation.
That separation, for the unsaved can cause eternal death or eternal separation.
Romans 6:23 For the wages of sin is death; but the free gift of God is eternal life in Christ Jesus our Lord.
--Death is separation from God for all eternity. The verse is a parallelism. It is a contrast between eternal life--a result of the free gift of God, and eternal death--a result of the wages of sin. Eternal "separation" (from God) is the death that is being spoken of here.
Death is always separation. With that in mind even though one has a sin nature, though he is depraved, he is not so totally depraved (as the Calvinists teach) that he is unable to choose--to receive or reject the claims of Christ. He is separated from Christ. He must make the decision to be reconciled to him. Being separated from God does not take away the ability to choose.