AP Photo/Orlin Wagner A student in line for his diploma wears a cap decorated with the cost of his education during graduation ceremonies at the University of Idaho in Moscow, Idaho, May 16, 2015. T his is a pivotal moment in American higher education—a crisis, you might say, if the term hadn’t been debased by overuse. The criticisms come from every corner and the bill of particulars is lengthy. The financial cost gets most of the attention. Since 1980, tuition has more than doubled at private universities and tripled at public institutions. Students have accumulated more than $1.2 trillion in debt, $300 million more than what Americans owe credit card companies. For-profit schools enroll about an eighth of all college students, many of whom end up saddled with mountainous debts and worthless degrees. Students from poor families have it especially rough. Half of all 25-year-olds from well-off families, but just a tenth of all 25-year-olds from poor families, have a bachelor’s degree...