What Albert Shanker has to teach us today.

Earlier and more clearly than most of his contemporaries, Shanker foresaw how "identity politics" would eventually tear apart the Democratic Party. It would rob liberals of the moral power of the argument for a colorblind society. It would fracture liberalism along racial, ethnic, and gender lines, pitting blacks not only against whites, Jews, and women, but also every other ethnic or minority group, as each stepped forward with separate, and competing, grievances. The special-interest sparring would prevent working-class Americans from ever making common cause on an agenda of economic betterment, to the detriment of all. Shanker all but begged liberals, through the 1970s and '80s, to concentrate on more bread-and-butter issues, to little avail.

When such appeals failed, Shanker glumly predicted the rise of Reaganism, including the defection of the so-called Reagan Democrats to the Republican Party. As early as the mid-1970s, Shanker also recognized the importance of "values" issues. He urged liberals to reach out to evangelicals and other working-class whites on concerns such as school safety and discipline in schools. Shanker argued, again correctly, that poorer families often cared more about such issues than did more privileged Americans, because it was in poorer neighborhoods that kids had the most to lose, educationally, in unruly classrooms.

In a similar spirit, Shanker opposed ebonics and the more extreme versions of bilingualism as misguided, middle-class movements championed by educators who had little understanding of the desire of much poorer parents for assimilation, as they scramble for a toehold in the middle class. (Shanker himself had not spoken a word of English until he entered New York City's public schools.)

At times one wants to weep for opportunities missed as one reads Kahlenberg's stirring account. There was Shanker—who was already anticipating in the early 1970s that child care would become a critical issue after women entered the work force en masse—lobbying to make public schools the site for day-care centers. But his ideas were ignored. So, today we have "multiculturalism" and "diversity" but not affordable child care for working parents.

At the core of Shanker's prescience was a single, revolutionary, but astoundingly commonsensical, insight: Poverty causes bad schools rather than the other way around. As Kahlenberg points out, the highly influential Coleman Report, issued in 1966, supported Shanker's notion, but it got lost in the debate about whether spending more money on schools was effective. More recent research—much of it by Kahlenberg himself, who is the leading proponent of class-based affirmative action—has found that racial integration, and most other reforms, have little effect in schools with overwhelmingly poor populations. But change the income balance within a school, and positive change follows: When the same poor students make up a smaller proportion of a student population—thus coming in contact with middle-class attitudes that promote learning—everyone benefits. In other words, peers' economic status matters as much as, or more than, peers' race or adults in transforming educational culture.

Shanker did make the occasional mistake. He was wrong on Vietnam (a war he supported), but he was right to be frustrated with both liberals and conservatives for cherry-picking which oppressive regimes to support and oppose based on their own domestic agendas. Shanker opposed them all—making no distinction between Pinochet's Chile, apartheid in South Africa, or communism in Poland. That's not to say he believed America should always police the globe. But he rightly observed that countries that suppressed unions were typically those that were already totalitarian, like China, or headed in that direction. For Shanker, the principle was the same everywhere: The ability of workers to organize is a basic human right, and a free and independent labor movement is no different from the other institutions, such as an independent judiciary, that are necessary for a stable democracy.

But Shanker was most ahead of his time in his interrelated views of race, social class, and education. And he may still be ahead of ours. Kahlenberg seems optimistic that Americans will embrace class-based affirmative action in their schools, and who wouldn't like to share his confidence that Shanker's moment has at last come: that we might heed his wisdom that narrowing the income gap will do more to help all poor people—including women, blacks, and Hispanics—than all the courses on self-esteem, etc., combined.  One sobering lesson of Shanker's life, however, is that such an endeavor requires fearless and persistent labor, not the quick big bang Woody Allen envisioned. Class-based affirmative action will be a tough sell, not because Americans prefer race-based affirmative action, but because tackling income disparities has fallen out of favor as a political priority. But if Shanker's life teaches us anything, it's that we shouldn't let obstacles stand in the way of forging ahead.