evidence: That history stands as a curious preamble to Nike’s decision to feature Colin Kaepernick, the erstwhile quarterback of the San Francisco 49ers, who has not played professional football in nearly two years, as a face of the thirtieth-anniversary "Just Do It" campaign. This is partly about the prerogatives of success: in 1988, Nike was trying to reverse declining sales and was still building its standing in sports beyond track and field. In 2018, though domestic sales in the sports-goods industry have lagged recently, Nike is a globally dominant brand and a supplier of apparel to the same N.F.L. that has rejected Kaepernick since he decided to kneel during the national anthem at the start of a game, to protest injustice and police brutality. (Kaepernick filed a collusion grievance against the N.F.L., and the league requested a summary judgment; following an arbitrator’s ruling, last week, it will go to trial. On Tuesday, in response to the ad, the N.F.L. released a statement that read, in part, "The social justice issues that Colin and other professional athletes have raised deserve our attention and action.")