I recall having read in certain Latin apologetic works on Church History that attributed the success of the Muslim invasions of the Christian world to the moral laxity and softness of Christians and their heresy (the Nestorians and Monophysites!). This may strike one as being an expression of Latin triumphalism, given the weakness of the Latin churches today
What if it is the case that the invasions were successful because the Christian polities were simply too weak? Must we find some moral blame for this? Or what if the polities failed because they were not Christianized enough -- not with respect to the "private" lives of individuals or expressions of orthodoxy, but because the polities lacked the excellence proper to it?
While those who lived with empire may have seen it as the only way to deal with external threats, what if they were wrong? Could it be said that the Byzantine theme system was close to being an expression of republicanism? Or were they effective purely for military reasons? What if despite the expression of public orthodoxy, the imperial government was not the form desired by God?
Would God save those who refuse to do what is necessary to save themselves? Lepanto, other victories have been interpreted as God intervening (especially through the intercession of the Mother of God). Still, Christians usually had to do their part in securing victory over the Muslims. While God's primary causality is not to be denied, and miracles are possible, what if God prefers Christian polities to participate in the Divine, in their own way, but attaining the excellence proper to them? Could God miraculously have intervened in preventing the Holy Land from being conquered by the Muslims? Did He withhold this help because of the private sins of the Christians living there, or as a consequence of other failures? Or did He have other reasons for allowing this to happen?