True that Freedom House did not exist in that era, but I for one endorse the criteria they apply as being as good a set of timeless, universal metric as any.

What specific situation will "trip the trigger" of a populace varies widely from place to place, culture to culture, and from era to era...but the perceptions that spark a populace to rise up are pretty damn constant. Freedom House does not set out to make that case, but the set of factors they apply to measure "freedom" are definitely in the beaten zone.