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.