America Tropicalmay aim to educate the theatergoer. But unlike the best political murals and operas for that matter (a category that includes John Adams' Nixon in China, Mozart's The Marriage of Figaro, and Anthony Davis' The Life and Times of Malcolm X, to name a few) its teachings are exhaustingly unappealing. If only Conte and his cohorts had mined Siqueiros' life for meaning and dropped the Pobladores and Rodney King from their musical fresco completely. There's enough in the artist's own story about the fight against oppression and redemption to fill a full-length opera. In drawing attention to Siqueiros' recently rediscovered mural, such a work would also literally make the walls speak.