AbstractPostwar “managed‐trade” policies feature low baseline tariffs combined with selective nontariff protection. This paper interprets managed trade as a rational strategy to undermine trade‐liberalization agreements in the absence of credible external enforcement. Analyzing the Kennedy GATT Round, I explore the calculus that led the United States to undermine across‐the‐board tariff reductions selectively by introducing nontariff barriers in industries with rapidly rising import demand. I show empirically that nontariff barrier dynamics across 216 industries support a rational‐cheating interpretation of managed