Harvard University’s president, whose championing of diversity initiatives made her a target of conservative critics, resigned this week. Photo: Steven Senne/Associated Press The management philosophy known as DEI, which had gathered momentum since 2020, has been under siege over the past year amid a collision of legal, economic and geopolitical forces. The Supreme Court struck down affirmative action in colleges, removing the legal rationale buttressing many diversity programs. An expected slowdown in the economy prompted companies to cut jobs and financial support for diversity, equity and inclusion initiatives. And the Israel-Hamas war and college presidents’ responses to antisemitism on campus...