For Sanders' proposals to be feasible in the long term, they must avoid putting the U.S. fiscal deficit on an unsustainable path. The only way that will happen is if productivity grows at a historically rapid rate and labor force participation rises to historic highs. Specifically, Friedman assumes that under Sanders, real gross domestic product growth will increase to a torrid 4.5 percent from its recent rate of just over 2 percent. That is even higher than the 4 percent being promised — unrealistically, I might add — by the Jeb Bush campaign. Friedman projects that under Sanders, median household income will soar to more than $82,000 by 2026, up from the current level of around $55,000. That would be an unprecedented bonanza.