Tropic Thunder

Tropic Thunder strays to the wrong side of the line that separates a satire of Hollywood vanity from an actual vanity project. There is too wide a schism between the jokes that work (Robert Downey Jr. as a pretentious actor working in “authentic” blackface, bellowing lines like “I don’t read the script, the script reads me” or “I don’t drop character ’til I do the DVD commentary!” in a gloriously offensive Fred Sanford growl) and the jokes that fall flat (the rest of them). It starts with a promising premise about three buffoonish movie stars wandering off set from the war film they’re shooting into a real war, but it’s too dumb, formless and desperately broad to successfully lacerate its satirical targets.