US Debt Level Thoughts: My Posted WSJ Comment To "Worry About Debt? Not So Fast, Some Economists Say"

My posted comment to The Wall Street Journal, "Worry About Debt? Not So Fast, Some Economists Say U.S. deficits may not matter so much after all—and it might not hurt to expand them for the right reasons" by David Harrison and Kate Davidson:

Interest expense on US debt is a manageable amount of the budget. In 2018, interest expense was 7.4% of the federal budget. In 2019, it is expected to be 8.5% percent of the budget and to grow to 12.5% around 2025. Unlike households or corporations, the US does not set aside or amortize principal. It waits until maturity of the debt. Its expense is almost exclusively interest payment. The average maturity of US public debt has been slowly increasing and is around 6 years now. When debt matures, the Treasury typically refinances the principal due with new debt. If 10 year US Treasury bond payments included amortizing principal payments, like residential household mortgages, it yearly debt payments would be about 4.5 times as much. With private debt, the inability to refinance or pay off the principal amount at maturity is an important component of default risk and the interest rate demanded. With US bonds, maturity and interest payment risk is a small risk factor. Low risk, low rate.