The weight of the evidence seems to be that presidential candidate Senator Amy Klobuchar has been abusive toward staff members to a degree that casts doubt on whether, despite the cheeriness and equanimity she displays in public, she lacks the temperament to be the best nominee the Democrats can put forward to run against Trump. New York Times columnist Bret Stephens has suggested that Klobuchar should resolve, and promise publicly, to be more considerate in her interactions with people who work for her. This strikes me as a good idea. So few politicians ever admit errors, it would be refreshing for a leading contender do so. In other respects Klobuchar stands out as an exceptionally promising candidate. She would be wise not to barricade herself behind a wall of rationalizations of her behavior.