Why is such a high US national debt not resulting in another great depression? The chart below shows that US national debt as a percentage of its GDP is at an all time high excluding the one during WW-II. While I'm not as well informed in economics as most of the people on this forum, I know that a national debt to GDP ratio of more than 100% means that the country is strongly headed in a direction where it cannot pay back its own debt. I have two questions.


Why is such a high US national debt, expressed as a percentage of its GDP, not resulting in another great depression?
What is a good mathematical measure(s) (if it is not national debt to GDP ratio) which will provide all the information needed to gauge the chances of US entering into a great depression/bad recession?


I am dying to know the answers to the above and I would greatly appreciate it if you can answer them for me.
You answered question (1) with your own chart. The United States had a “high” debt-to-GDP ratio in World War II - and there was no subsequent depression. (There was a sharp recession as a result of demobilisation, but that was short-lived.)

For a country that borrows in its own currency, there is no obvious reason how a high debt-to-GDP creates recession risk.

There is no easy answer to (2). We are currently headed into the greatest economic contraction since the Great Depression, and the cause was a pandemic, which would not show up in a standard mathematical economic model.