I often hear people talk about 'cycles of struggle,' or 'deepening cycles of struggle.' I think this means that resistance movements tend to happen in clusters or waves, perhaps in response to specific historical crises, or perhaps just because one group or city or whatever will inspire/embolden several others, causing momentum to build.
I wonder if anyone can elaborate on this. Who thought of this idea? Were they talking about a specific set of events? Are there any strategic/historical implications I'm missing? (I'm guessing there are...)