This biopic of legendary Broadway producer-director-songwriter-star George M. Cohan may be the most blatant piece of flag-waving American jingoism the screen has ever seen (it came out during the early days of World War II), but considering Cohan wrote the “The Yankee Doodle Boy,” “You’re a Grand Old Flag” and “Over There,” among other indelible tunes, at least it’s true to his art. What’s truly artful, however, is James Cagney’s Oscar-winning performance as Cohan. Best known, to this day, for his volatile turns in gangster classics such as The Public Enemy and White Heat, Cagney originally was a song-and-dance man like Cohan, and here you can see him gleefully returning to his roots. Cagney’s volatility is still here – indeed, it’s the key to his dancing. He’s shorter than almost everyone else on the screen, and you get the feeling that there is too much energy bottled up in that tiny body, that it has to come out some way. As he taps, spins and literally bounces off the walls, Cagney’s loose limbs and rigid back given him the appearance of a marionette. He’s so light on his feet, you wouldn’t be surprised if he suddenly lifted into the air. Director Michael Curtiz (Casablanca) dutifully delivers a series of big production numbers, but they’re stodgy and cumbersome – almost the exact opposite of the star at their center. He’s the only spectacle the picture needs.