Considering that this film takes place in Washington, D.C., the fact that it concentrates on the four-legged rather than the two-legged rodents who inhabit our nation’s capital constitutes a waste of a perfectly good title. In any event, this sputtering documentary from James Felter roots around the Beltway’s back alleys in search of the ubiquitous titular critters. Along the way, it discovers a handful of none-too-savory characters and passes a scathing judgment on our trashy, disposable society. So what else is new? Aside from its distasteful subject matter, the crippling flaw in “Rats” is its lack of focus. One minute the film tries to elicit our sympathy by anthropomorphising the rats and ridiculing a gun-toting neighbor whose favorite hobby is nighttime rodent hunting. Then it turns right around and dwells on the skittering vermin in such grotesque detail that you’ll be tempted to squish your nephew’s hamster. Perhaps more distasteful than the rats are the humans in the film. There’s the ranting and bickering gay couple who can scarcely contain their disdain for the low-income blacks who live nearby. There’s the out of touch city worker who seems determined to do little more about the infestation than spout bureaucratic doublespeak. And let’s not forget the two dumpster-diving crack addicts who, oddly enough, seem to be the most normal people in the film. It’d be nice to say something intellectual like “Felter effectively uses the lives and deaths of the rats as metaphors for the human condition…” but I’d be making it up. Instead, his intention either seems to be to gross us out — garbage men luridly describing maggot slime — or to shock us — gratuitous close-up footage of an unfortunate rat meeting its thrashing demise in a big mouse trap. In the end, the most profound message behind “Rats” seems to be that trash in your yard lead to rat infestations. Well, duh. We’ve known that since the Black Plague. If that’s the best argument this film makes, use the seventy-five minutes you’d burn on “Rats” to clean your garage instead.