One of my favorite moments from Dr. Dan Toft's history class in college was when he talked about economic downturn and noted (paraphrase), "There is no more resentful and angry people than those who have been bourgeois but have lost that status." Back in the Middle Ages, these were the people who knew enough about organization to have successful revolutions, like the Peasants' Revolt of 1381. Recall, as well, the folks who brought us the Nazis; the system didn't work for them, so they instituted some radical changes.
As Brooks notes, we're about to have a large group of people fit that very definition. Their anger will seethe; imagine a GM line worker who has worked to send his children to college. First, he loses his job, and has no education to fall back on. Then, if he's sent his children to college, they can't get a job and have to move into the basement, or work at Wal-Mart or McDonald's. Or, he can't send his children to college in the first place. He thinks back on goals unfulfilled, personal failures.
Whan adam delffid and eve span, Who was than a gentilman?
[1381 in Brown & Robbins Index Middle English Verse (1943) 628]
Brooks actually depicts the economic downturn's possible effects a little to sunnily, in my opinion.
This recession will probably have its own social profile. In particular, it’s likely to produce a new social group: the formerly middle class. These are people who achieved middle-class status at the tail end of the long boom, and then lost it. To them, the gap between where they are and where they used to be will seem wide and daunting.
Racism, crime, xenophobia -- more like this. We've already seen desperate expressions at Sarah Palin rallies; those weren't corporate CEO Republicans shouting "kill him!" It was the disenfranchised, blue collar Republican.
In this recession, maybe even more than other ones, the last ones to join the middle class will be the first ones out. And it won’t only be material deprivations that bites. It will be the loss of a social identity, the loss of social networks, the loss of the little status symbols that suggest an elevated place in the social order. These reversals are bound to produce alienation and a political response. If you want to know where the next big social movements will come from, I’d say the formerly middle class.