On May 10 the National Trust for Historic Preservation joined countless local historians who, over the years, have maintained a conspiracy of silence about one of America's most shameful secrets.

Between 1890 and 1968, white Americans established thousands of towns across the United States for whites only. Many towns drove out their black populations. Others passed ordinances that prohibited African Americans after dark or kept them from owning or renting property. Still others stayed white by boycotting, harassing, and even killing nonwhites who ventured in.

The National Trust has just listed one of these towns, Kenilworth, Illinois, among "America's Eleven Most Endangered Historic Places." Kenilworth, Chicago's richest and most prestigious suburb, is "endangered" by McMansions. The National Trust describes Kenilworth as "an ideal suburb" that offers "a welcome escape from the dirt, noise and crowding of the city."

Surely no all-white suburb can be "ideal."

Joseph Sears founded Kenilworth with four key provisos: "Large lots, high standards of construction, no alleys, and sales to Caucasians only." "Caucasians only" was interpreted to exclude Jews as well as nonwhites. Later, Sears realized he had forgotten to allow for live-in servants and sent a note to each resident of Kenilworth; none objected. By 1950 the suburb had 79 African Americans — every one a maid, nanny, or other servant.

A Jewish family, the Spiegels of mail-order catalog fame, managed to move into Kenilworth in the 1920s, but they may have been the last for decades. Certainly in the 1950s Kenilworth was notorious for keeping Jews out. Kenilworth may also have excluded Catholics, but by the 1950s that prohibition was loosening. In the 1970s, Kenilworth let in Jews.

In 1964, a black family, the Calhouns, finally moved into Kenilworth. Teenagers burned a cross on their lawn, but they stuck it out for twelve years, making some friends in the community. In 2002, however, the town's leading realtor did not think that a single black family lived in Kenilworth.

Kenilworth's overwhelmingly white character makes it harder for nearby interracial suburbs like Oak Park to stay interracial. Over time, some white residents of places like Oak Park, amassing more money and wanting to move to a still more prestigious suburb, relocate to Kenilworth. Wealthy black families don't, knowing Kenilworth's racist past.

Precisely that past is obscured by the National Trust for Historic Preservation. Nowhere does the Trust mention Kenilworth's racial and religious apartheid, even though it has been a defining characteristic of the town. Such obfuscation hardly serves history.

Instead, it preserves the smokescreen essential to the prestige of elite white suburbs. This prestige depends upon the "paradox of exclusivity." Metropolitan areas have long been ranked more prestigious to the degree that they exclude African Americans (and working class people, Jews, etc.). Living in such "exclusive neighborhoods" connotes status. Such places want to be all-white, but they don't want it known that they are all-white on purpose. Open exclusion implies prejudice and is not prestigious.

Ironically, the same processes that led to sundown suburbs also led to the distress evident in the other two neighborhoods that made the National Trust's endangered list, "Over the Rhine" in Cincinnati and the majority-black parts of New Orleans. Sundown suburbs cause inner-city decay, because as whites seek status in white towns, they withdraw not only themselves but also their sympathies, connections, and investment dollars from formerly interracial areas.

The National Trust concludes its nomination of Kenilworth: "The historic character of this very special place must be protected." First, the Trust needs to revise its write-up to acknowledge Kenilworth's racial past, because the historic character of this very special place must be exposed.