[davetufts]

From the article: "The first surprising thing was how fast the national debt has grown in the last 30 years."

The sharp incline coincides with Nixon's 1971 end of the Bretton Woods system. Domestically the dollar has been off the gold standard since 1932, but up until 1971 foreign banks could still redeem US dollars for gold. Since gold is a limited commodity there's a limit on how much we can spend or borrow. Once that tie was broken, we were free to run unlimited debts.