They are supposed to be dispassionate dispensers of Pure Justice, icy islands of emotionless calculation. In short, umpires should be acute Republicans.

Will’s line satirizes the ideal of the umpire (and, by analogy, the judge) as a neutral, mechanical applier of rules—an “icy” figure who simply calls balls and strikes without values, temperament, or discretion. By adding “In short, umpires should be acute Republicans,” he turns the supposed neutrality into a partisan jab: the posture of pure objectivity is itself a political stance, associated here with a conservative preference for rule-bound restraint and suspicion of empathetic or “living” interpretation. The humor depends on exaggeration—no umpire is truly emotionless—and on exposing how claims of dispassion can mask ideological commitments.