Valkyrie puts forth the idea that not all Nazis should be categorized as either ferocious barbarians or craven order-followers. We knew this, of course, from Schindler’s List. And from history. And from not being idiots. And yet we watch. We are curious.

It is at once a caper movie, a period piece, and a true story. It is stuffed with charismatic English thespians — Kenneth Branagh, Tom Wilkinson, Bill Nighy, Terence Stamp, even Eddie Izzard — and topped off quite improbably with Tom Cruise. It is directed by Bryan Singer, the guy who broke through with a gang-of-criminals puzzle thriller (The Usual Suspects) and promptly graduated to comic-book superhero blockbusters (X-Men, X2, Superman Returns). It is hard, therefore, to account for why Valkyrie seems somehow smaller than life. Maybe it’s that the movie tries to make a point of quietness, for suspense’s sake, and accordingly solicits stagnation.

But let’s not go so far as to call it Mission: Impossible: Bore. That’d be fun to say, but not wholly accurate. As screenwriters Nathan Alexander and Christopher McQuarrie (the latter also of The Usual Suspects) seem to understand, the mission in question here, a Nazi colonel’s actual plot to assassinate Hitler with a briefcase bomb in 1944, proved so tantalizingly possible that it’s still compelling even in spite of failure: Knowing what happened is partly why we want to know what happened.

Operation Valkyrie was the pre-existing bureaucratic contingency plan for Hitler’s death or incapacity, approved by the chancellor himself and cunningly rewritten by his would-be assassin to divide the party against itself and conquer from within. The willful colonel, played by Cruise, is Claus von Stauffenberg, a German nationalist who lost one eye, seven fingers, and his patience to an arguably avoidable Allied bombing raid in Tunisia and decided thereafter to send his Führer a personal FU.

Go ahead and laugh, but the casting makes a lot of sense. Crisply procedural self-importance is Cruise’s gift, and proving as much is all Valkyrie really asks of him. Actually, his Stauffenberg is a model fascist: underdeveloped and overdetermined, a man of 99 percent action and 1 percent character. Sure, he has a wife (Carice van Houten) and children to think of, but what matters more is that circumstances have deposited him on the right side of history. As he becomes fearlessly, almost mechanically heroic, we will reflexively root for him.

Besides, he’s a good man to have in charge, given the infighting and indecision among his variously reluctant co-conspirators, who tend to outrank and obstruct him — whether because they’re two-faced (Wilkinson), dithering (Nighy), or just temperamentally non-militaristic (Stamp). Singer, for his part, would like to make clear that he has all of their backs. He suits them up in the shiny boots and the starchy trench coats, stages them among flags and fortresses as far as the eye can see, and lets them speak freely with their own unvarnished British and Cruiseish accents.

Perhaps a firmer hand was in order; this is not a democracy! Singer tries neither for the Spielbergian noble Nazi of Schindler’s List nor for the Spielbergian cartoon Nazi of Raiders of the Lost Ark; he’d deserve a moviemaking medal of honor if only he hadn’t so tepidly split the difference.