Also, part of the reason presuppositionalism comes up in these kinds of debates is because atheists frequently hold judeo-christian presuppositions without even considering that full-bodied atheism won't allow them to hold those positions.
It's easier to defend Christianity as the truth when we actually open the scriptures next to other religious texts. Someone I know once proffered the notion that all religions are equally valuable and they all lead to the same place. That notion goes away quickly once these texts are opened next to each other and compared. This individual in particular was defending the teachings of the Quran until we opened them side-by-side and compared what each had to say. He has since abandoned his atheism and is now a Christian.
- Z