Several Hoover Institution scholars write,
In recent months, we have seen an inevitable rise in interest rates from their low levels of recent years. Rising interest rates and increasing deficits threaten to build upon each other to send public debt spiraling upward even faster. When treasury debt holders start to doubt our government’s ability to repay, or to attract future lenders, they will demand higher interest rates to compensate for the risk. If current spending and tax policy continue unaltered, higher interest costs will have to be financed by even more debt. More borrowing puts more upward pressure on interest rates, and the spiral continues.
If, for example, interest rates were to rise to 5 percent, instead of the Trump administration’s prediction of just under 3.5 percent, the interest cost alone on the projected $20 trillion of public debt would total $1 trillion per year. More than half of all personal income taxes would be needed to pay bondholders. Such high interest payments would crowd out financing of needed expenditures to restore our depleted national defense budget, our domestic infrastructure and other critical government activities.
See the post from John Cochrane, one of the authors. If investors, including the Chinese government, grow leery of U.S. government debt, then my guess is that we will see the tactics that are known as “quantitative easing.” That is, the Fed will grow the supply of reserves, so that it and the rest of the banking system absorb a lot of government debt. The trick will be to keep banks from doing a lot of lending other than to the government. My guess is that paying a low rate of interest on reserves won’t be sufficient, and instead some form of financial repression will be needed. By that I mean regulating banks in such a way that buying government debt is approved while making business loans is frowned on.