They were the pink slips that helped change American liberalism.

Forty years ago—on May 9, 1968—the local school board in Brooklyn's black ghetto of Ocean Hill-Brownsville sent telegrams to 19 unionized educators, informing them that their employment in the district was terminated. Eighteen were white. One black teacher was mistakenly included on the list but reinstated almost immediately after the error was discovered. Although there was some ambiguity in the notices about whether the teachers were being terminated or merely transferred to another district, members of the Ocean Hill-Brownsville board repeatedly said they had "fired" the teachers, and Rhody McCoy, the local superintendent, told The New York Times: "Not one of these teachers will be allowed to teach anywhere in this city. The black community will see to that."