Thirty-seven years ago, the baseball player Curt Flood, fresh off his final, dismal year as a professional athlete, published a memoir titled “The Way It Is.” It cannot be called a great book, but its literary quality was a secondary concern. In the autumn of 1969, Flood had refused to be traded from the St. Louis Cardinals to the Philadelphia Phillies. He sat out the 1970 season, while he fought a lawsuit that eventually reached the Supreme Court. He lost his case, but it resulted, a few years later, in the creation of free agency. Flood’s protest earned him an enormous amount of public scorn—including daily death threats—and “The Way It Is” was his chance to respond. In one section, he recalls a piece of mail (addressed “Dear Nigger”) that foreshadowed the coming deluge:

The outlines of Flood’s story—black athlete takes a principled stand and is maligned for his “ingratitude”—are familiar. The theme connects Flood to Muhammad Ali and, now, to Colin Kaepernick. Most significantly, it gives the lie to a facile mythology about sports transcending the divisions of American society; they have just as often been a barometer of the resistance to social change, even when that change might bring the country more in line with its purported ideals. The tension between ideals and reality and the way that they collide in sports is the subject of the video “All in the Game: The Black Athlete in America.” As the video shows, it would have been naïve to suspect that the racial fault lines of the Trump era would not find expression in athletics. (The filmmakers launched the project a week after the President hurled racially loaded insults at football players and disinvited the N.B.A. champions from a White House visit.) The common lament of this fraught period is that precious little seems to be beyond politics. But, if the history of black athletes is indicative, the larger concern is how one could not have known this to be the case all along.