The Fourth Turning by William Strauss and Neil Howe (pg. 258)

When the society approaches the climax of a Crisis, it reaches a point of maximum civic power. Where the new values regime had once justified individual fury, it now justifies public fury. Wars become more likely and are fought with efficacy and finality. The risk of revolution is high–as is the risk of civil war, since the community that commands the greatest loyalty does not necessarily coincide with political (or geographic) boundaries.