Let’s imagine a nation with the following characteristics:
-- large but not unmanageable amounts of debt of long-term debt;
-- a very high credit rating;
-- low or even negative interest rates;
-- a stable but slow-growing economy;
-- deteriorating and outdated infrastructure;
-- an aging population that entails rising health-care and retirement spending, and;
-- a tremendous demand for fixed-income securities, the longer the maturity the better.
Don’t leap to the conclusion that the nation is the U.S.; if it were, I would have had to add a bullet point describing it as having a dysfunctional government paralyzed by partisanship.
But regardless of the nation in question, the appropriate approach to financing this debt suggests a long-term bond -- whether with a 30-year or even 50-year maturity.