Paul Glastris thinks progressives should be concerned with how the No Child Left Behind Act punishes gifted students - the idea being that if teachers are required to put the most effort into helping the least gifted students to bring them up to proficiency, gifted students who need to be pushed to excellence get short shrift.
This strikes me as backwards - if anything, progressives should be less concerned with gifted students than with the most unfortunate students. If we're willing to sacrifice the incomes of the wealthy with progressive taxation and social welfare programs to help out the most needy, if we're willing to sacrifice the most top-notch health care in order to extend coverage to the 40 million who live in fear of financial catastrophe if they get in a car accident, why can't we sacrifice a bit of educational excellence to achieve broader educational proficiency?
As Paul Glastris says, with fewer excellent students, we'd probably end up with fewer scientists, intellectuals, engineers, etc - the people who create innovation and thereby prosperity and better standards of living. But this is equally true of progressive taxation and national health care: high marginal tax rates discourage work and investment among high earners who tend to be the most productive; and national health care reduces the incentive for drug companies to develop new drugs, because they're no longer guaranteed the ability to charge outrageous prices. Equality and excellence are values in tension, and while it's not exactly either/or (clearly you can put more effort into educating both the most and least proficient), you do have to make your trade-offs at some point.
Maybe that's so much the worse for equality. But it seems to me that if you're in favor of progressive taxation and national health care, consistency requires you to favor an emphasis on educating the least-gifted. The NCLB Act has a lot of problems, but from a progressive point of view, shortchanging gifted students while focusing on the least proficient students isn't really one of them (at least in principle - obviously it's bad if it fails at this goal in practice).