With cynics and extremists exploiting patriotism these days, the prospects for Captain America looked dim. But Joe Johnston's adaptation of the Marvel comic book exalts the virtues of optimism, decency, and perseverance in a rousing adventure of old-fashioned adolescent exuberance. Credit Chris Evans, who portrays Steve Rogers, the 4F shrimp transformed into a star-spangled superhero, with a rueful innocence and sneaky humor reminiscent of Jimmy Stewart. Likewise, Johnston, as in his underappreciated The Rocketeer (1991), shows a genius for creating an alternative past, a World War II fought with weapons combining retro quaintness and nightmarish futurism. Johnston is also smart enough to poke fun at the hero's hokiness — before fighting Germans in earnest, the Captain is socking Hitler in a stage show — but he finds a wickedly worthy opponent in the Red Skull, played with a Werner Herzog accent by Hugo Weaving.