"Humanity has been grappling with these questions throughout human history,” [the President] told the group, speaking of the tension between the compassionate and murderous acts religion can inspire. “And lest we get on our high horse and think this is unique to some other place, remember that during the Crusades and the Inquisition, people committed terrible deeds in the name of Christ. In our home country, slavery and Jim Crow all too often was justified in the name of Christ.”
The deep problem with his Niebuhrian style isn't that it's too disenchanted or insufficiently pro-American. It's that too often it offers "self"-criticism in which the president's own party and worldview slip away untouched.