... Only hours before Sunday’s debate, Mr. Biden’s campaign announced that he is “adopting Senator Sanders’ proposal”—from a bill Mr. Sanders sponsored in 2017—to fund tuition-free college for families who earn under $125,000 a year. This probably would cost hundreds of billions of dollars over a decade. It could devastate private colleges and liberal arts schools. It would banish economic incentives, forcing universities to compete, more than they already do, over whose climbing wall is the gnarliest. Lest Elizabeth Warren feel left out, Mr. Biden is adopting her plan “to fundamentally reshape our bankruptcy system.” To pick two of her...