In explaining how hard it is to determine which upwind state’s air pollution “contributed significantly” to a downwind state’s problems meeting air quality standards—and thus the need for the EPA to use its best judgment—Deputy Solicitor General Malcolm Stewart drew an analogy to a basketball game. In the clip below, you’ll hear the Deputy Solicitor General discuss how the EPA’s task is similar to that of a basketball coach after a losing game: A coach might be quick to identify a missed half-court shot at the buzzer that would have won the game—had it been successful—as the “but-for” cause of the loss—that is, but for that missed shot, we would have won. But when speaking in terms of significant contributions to a bad result, a coach is more likely to identify several additional errors that could have been avoided throughout the game—a missed layup, a turnover—rather than focus only on the failure of accomplishing a long-shot attempt. The EPA is similarly given the difficult responsibility, under the Clean Air Act, of figuring out which state’s pollution has “contributed significantly” to a neighboring state’s difficulty in meeting federal air quality standards, a task that involves a variety of factors and variables.