Re: Flipping Out       So why not just “let the river run
freely,” as Checker proposes? Let schools change naturally, as
their neighborhoods are changing naturally, rather than try to
“change the direction of the river”?  It’s a classic collective-
action problem. Lots of people would choose a diverse school,
defined as, say, roughly split 50/50 between poor children and
middle-class peers. (In reality, most people, rich and poor,
probably prefer a 70/30 split in favor of the middle class.) But
few middle-class parents will agree to be the first ones to
“integrate” an all-poor school. Once a school starts
gentrifying, though, many middle-class parents will join
in—creating a “flood,” in Checker’s parlance. But without flood
walls, the school will inadvertently become uniformly middle
class, and we’ll have missed the opportunity of diversity.  I’m
not spouting theory. Look at Brent Elementary on Capitol Hill or
Ross in Dupont Circle. Several years ago, there was an
intentional effort to recruit middle-class fam