This paper investigates the macroeconomic factors that explain antidumping decisions in the US International Trade Commission. Johansen's cointegration test results show that there is a long run equilibrium relationship between growth of the percentage of affirmative antidumping decisions and trade balance. The error correction model shows that there is a causality running from the latter to the former. Growth of the percentage of affirmative antidumping decisions is revealed to cause slowdown in economic growth. Partisan characteristics are observed in the Commissioners' antidumping decisions.