Secular Cycles / Structural-Demographic Theory, associated with researcher Peter Turchin.
A framework saying complex societies rise and fall on long cycles of roughly 200-300 years.
It points to two pressures that build toward collapse: too many elites competing for too few top spots ('elite overproduction') and worsening conditions for ordinary people, with the model placing the 2020s at a disintegrative peak.
It gives a dated reason to expect major instability right now, which the engine uses as a timing signal.