I know, it's also the same poll that shows 20% "no chance" and 40% "less likely". When you take into account that most polls show roughly 40-50% of Republican voters either mis-identify or do not know Giuliani's positions on abortion, homosexual rights or gun control it's fairly easy to understand why he would lead even amomg white Evangelicals.
Let's see where the numbers go when his positions are widely known.