For the last 70 years, American higher education was assumed to be the pathway to upper-mobility and a rich shared-learning experience. Young Americans for four years took a common core of classes, learned to look at the world dispassionately, and gained the concrete knowledge to make informed arguments logically. The result was a more skilled workforce and a competent democratic citizenry. That ideal may still be true at our flagship universities, with their enormous endowments and stellar world rankings. Yet most elsewhere, something went terribly wrong with that model. Almost all the old campus protocols are now tragically outdated or...