To his credit, the mayor showed up, promised specific actions and responded to a litany of shouted, angry citizen complaints. He also was shown facing the kind of real-life crisis and accountability to which chief executives are subject and legislators generally are not.

Yet what he did not do was emote. There was no Clintonian “I feel your pain” moment or Obama-esque discussion of the larger legacy of racial injustice that has laid open a gulf of mistrust.

Those who know him — and I do — could see the anguish etched in his furrowed brow. But his answers were delivered in a factual, almost clinical, manner, more in keeping with his prior life as an analyst for McKinsey & Co. than the ministerial role called for by an episode in which a life was lost.

For Buttigieg, the episode underscored what may be his greatest political obstacle for the nomination of a party in which African-Americans represent a quarter of the vote. It is almost impossible to win the nomination without substantial black support. This episode was a blow, but it also highlighted what may be a greater barrier.