Reading the article, Elfenbein knew that McKinsey was in conflict with what was until then the defining arc of his life. His fiancée—Elfenbein was days away from his wedding—was blunt. “If you don’t quit right now, you don’t stand for anything,” she said.

He laid out his recommendations in bullet points. Among them: a demand that McKinsey make a public apology for working for ICE and “stop saying we would do this work again.” Another: “Stop using legality as the barometer for ethicality.” On this, he was particularly biting, adding a parenthetical phrase: “If we helped southern states ‘improve agricultural asset yield’ in the 1850s would we still stand behind that? Our guidance so far would indicate the answer is ‘maybe.’ ”

A few days later, D’Emidio, the partner in charge of the ICE project, sent a mass email of his own. Subject: “Call for reconciliation and healing.”

In bullet points, he wrote of his deep sympathy “for those of you whose families and friends live in fear of my client,” as well as guilt “for having been the cause of so much angst, shame, mistrust, and anger for so many of you.”

But then his email took a turn as he described how hurt he was “by the stinging words of some emails accusing me of having no sense of ethics, purpose, or values,” anger at the “vilification” of his colleagues on the ICE project, plus “frustration” over what he said were “inaccurate portrayals” of the team’s work. He then said he was proud of the “impact” his team had. D’Emidio called for dialogue “with the hope that we can heal each other’s wounds.”