Whether the medieval Crusades can be deemed justified still elicits debate. Thus, when President Obama cited the Crusades as evidence of wrongful Christian violence in the past (as a strategy for explaining how Islam as a religion should not be singled out for blame on grounds that it is especially prone to violence), friends of the Crusades stepped forward to defend the noble spirit of self-sacrifice that animated the Knights Templar and other Christians who had sought to protect their co-religionists from harm and to regain the inheritance of Christ from Muslims. Indeed, if we survey the vast literature on the Crusades, it can be normatively divided between those who paint this religiously motivated warfare in dark strokes (as premised on a misguided belief in divinely sanctioned violence) and others who express their admiration for the high values that motivated the crusaders and even hold it up as an example of Christian behavior that could be applicable in all times and places.
Reichberg, Gregory M. (2018) Journet on the Impossibility of Christian Holy War, Nova et Vetera 16 (2): 511–541.