Explain why the inflation that John Cochrane fears would “bring stagnation rather than prosperity.”

John H. Cochrane, a professor of finance at the University of Chicago, thinks we face the risk of inflation, and if inflation does break out the Fed will not have the ability to stop it and it will “bring stagnation rather than prosperity.” The source of the inflation risk that Cochrane fears is not the Fed but fiscal policy. He worries that budget deficits have made U.S. government debt too large, and with no plans to return to budget surplus on the horizon, debt will keep growing. Today, foreigners are happy to hold and to keep buying the debt. But if they decide the risk of continuing to hold the debt is too high, they will dump the debt and buy real assets, whose prices will skyrocket. If inflation takes off, “it will happen with little warning.”