I think there is also the question of the "debt bomb," in the U.S. that no one really wants to talk about. The debt bomb seemed uncomfortably close to detonating a month ago when gasoline went over $3.

We aren't a country similar to the 1930s, when a lot of people lived on farms or small towns where they were fairly self-sustaining. People in those days tended to save for rainy days. Right now the U.S. savings rate is zero, and the government is into deep deficit spending to try to keep the economy going.

That's why I can never discount the "cliff" theory. We don't have a parachute if the debt bomb goes off.

It's certainly a concern.  But other countries have had economic crises.  Such as Argentina.  It was unpleasant, but it wasn't the sudden collapse of civilization as they knew it.
Exactly, Argentina and many other declining states find that from one generation to another the changes are persistently negative, but it becomes harder and harder to realize what has been lost unless you have a reference point - for instance, would East Germany have looked that if it were not sitting right next to the prosperous West Germany?

What we might find (one possibility) is that we slowly slip into a decline that we can only diagnose long after the fact when it might not be fixable.

If you haven't read Jared Diamond's "Collapse", I highly recommend it. Not all Collapses are the same. Some take weeks, some take years, some take many generations.

I love Jared Diamond.  I've been reading him since he began writing columns for Discover magazine, twenty years ago.  (One of his early articles was "The Worst Mistake in the History of the Human Race" - which he argues was inventing agriculture.)

Collapse is great.  I also recommend Guns, Germs, and Steel, his previous book (which won him a Pulitzer).  It's sort of the complement of Collapse: it explains how Western civilization came to dominate the world.