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-- deteriorating and outdated infrastructure;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.