The presupposition of biblical inerrancy serves as a guarantor of the truth of their "biblical" worldview.  For them, if you could prove that there was a single error in the Bible, you would undermine faith in God (-- thereby pressing God into service as a guarantor for their view of the world).  Of course, identifying an error in the Bible is impossible.  All genuine inquiry has been precluded by the presupposition of scriptural inerrancy.  It is perfectly circular reasoning.  

It is also perfectly idolatrous.  Ultimately, their faith is in a book.  They will-to-believe in a perfect Bible.  That is a precondition for belief in God.  In their eyes, if God can't be trusted to hand them a perfect book revealing a perfect system of laws from which they can logically deduce a perfect way to order the world, God could not be perfect.

The first thing those of us who live outside of this closed system of thought and belief need to realize is that, however inadequate we believe their faith to be, these people have a strong faith.   Those who accept their initial presupposition receive a worldview that gives life a clear and unambiguous meaning, has logical consistency, and answers a psychological need for order and certainty.  

If they were content to live out their faith within their own ecclesial communities, they would pose no threat to those who are unwilling or unable to live by their presuppositions.  Christian Reconstructionists, however, are not content to exercise their faith within their own communities.   They believe they have been commanded by God to establish their understanding of God's order over the entire earth and to exercise dominion over all peoples.  That is why it is important for us to understand their thought, to expose its fallacies, and to find ways to encourage its adherents to deepen their faith in God and grow in their understanding of the ways that God relates to mankind.