Kung fu has become the primary engine for the American action film culture. The elements of martial arts – the gymnastic athleticism, the mystic spirituality, the nimble feats of lethal dexterity in which an agile-limbed fighter takes down an enemy with a well-place blow to the knee or arm or whatever – have become the mode for delivering adrenaline-pumping blasts of cinematic “excitement.” But for every movie like “Crouching Tiger, Hidden Dragon” or “The Matrix,” movies in which the spirit of martial arts is treated with the grace and elegance it deserves, we get a half a dozen movies like “Cradle 2 the Grave” in which the martial arts have been reduced to choppily edited conduits for much lame, macho Steven Seagal bluster and attitude.

I would have loved to have been a fly on the wall for the high-concept pitch for “Bulletproof Monk:” It’s “Crouching Tiger” meets “The Matrix” starring “American Pie’s” Stifler! The movie takes the anti-gravity fighting of the former – the way the heroes seemed to float in the air and on the treetops – and the “bullet-time” special effects of the latter, and proceeds to leech the sophistication out of the both of them. The director, Paul Hunter, is a music-vid veteran, so it may be no surprise that “Bulletproof Monk” comes off like “Crouching Tiger” reduced to a frenzied rubble.

The movie opens in 1943, with a sharp-faced Nazi commandant (Karel Roden, one of the Eastern European maniacs in “15 Minutes”) and his crew invading a sacred Tibetan monastery that’s home to a magical, mystical scroll. And just when we thought that the Indiana Jones movies used up the patent on using Nazis as cartoon bad guys.

The scroll has many powers, such as the prevention of the onslaught of age (Joan Rivers would love to have a piece of the parchment) and the ability to shape the world into whatever image the one who reads it imagines. It has been entrusted to a young monk (Chow Yun-Fat) who has been charged with protecting it for the next 60 years.

Chow, who isn’t necessarily bulletproof but can certainly dodge bullets with the best of the them, kicks and chops his way through the faceless bad guys and escapes. Cut to 2003 and the monk – he has no name – is in Toronto passing for New York City, on the run from his now decrepit nemesis and the man’s goons, who in typical fashion, are outfitted in three-piece suits and earpieces.

So far, so usual. So it’s no surprise that a wisecracking sidekick turns up, this time in the form of cocky pickpocket Kar (Seann William Scott). Kar is pegged as the prophesied heir to bodyguard status for the scroll, but he of course balks at becoming enlightened – as he says this is America, home of hot dogs not enlightenment.

“Bulletproof Monk” is not a movie that you would call enlightened. It’s not even a movie that you would call intelligent. It’s a movie that you could say is lacking in anything resembling smarts, coherence and purpose. The movie is a silly and simplistic tale that far too often crosses the line between dumb fun and just plain dumb.

Too much implausibility puts a strain on the movie, which has the effect of sapping the fun from the proceeding. In the fight scenes, Chow is called on not just to do the usual kung fu moves, but to do things that are basically limited by a thing called the laws of physics. He flips, flies and practically dances through the air, and soon enough Scott is following his lead. When this effect is done in “The Matrix” there is a believable reason for this to be happening, and the poetic, magical-realistic tone worked for “Crouching Tiger.” Setting the action in the real world makes the leaps through the air look rather goofy, with or without pat, cop-out explanations. It hardly helps matters that the special effects are almost hilariously unconvincing.

Chow strides through the movie with a look of humored determination as if trying to hide his embarrassment for the folly he’s stuck in. Scott, meanwhile, is charismatic but plays Kar with the same swagger and ironically cocky he strutted Stifler through. Model Jaime (formerly James) King shows up as a heiress/ pouty bad girl/ bland love interest. Together Chow and Scott offer a few moments of stupid amusement, but not enough to save “Bulletproof Monk” from itself.