by Sue Finley and Dan Ross Few commercial sectors appear immune from the current administration's sweeping import tariffs, and that includes horse racing's biggest Saturday of the year, with Japan's participants in the GI Kentucky Derby potential targets of the trade war. Stressing a general air of uncertainty surrounding the tariff specifics, Matt Haug, general manager of International Racehorse Transport (IRT), said that, as he and his customs broker understood the situation, the Japanese-trained Luxor Cafe (American Pharoah) is exempt from any tariff being a U.S.-bred runner. For foreign-bred horses--like...