”The Crazies” rocks. This remake of George A. Romero’s 1973 biological warfare shocker is a trim, taut, terrifying essay in homespun horror.

If Pa in Grant Wood’s ”American Gothic” had impaled Ma on the end of that pitchfork, the scene would fit right in.

The setting is bucolic Ogden Marsh, Iowa, the sort of upright farm community where the high school baseball game is the highlight of the week’s calendar.

Sheriff David Dutton (Timothy Olyphant) knows everyone by name, so when the town drunk wanders onto the diamond, shotgun in hand, the lawman tries to peaceably talk him down. But there’s something other than alcohol in his blood, and the confrontation is only the beginning of the town’s troubles.

Something very bad is circulating among the good folks of Ogden Marsh, and in three days time Sheriff Dutton will be just about out of bullets.

This is a slick fearjerker, filmed with brilliant visual style and edited with sadistic precision. The town has a frayed, lived-in look, and when director Breck Eisner begins turning off the lights and setting homes on fire, it transforms nicely into an atmospherically chilling hell on earth.

Horror movies always gain resonance when they connect to the mood of the day and the tagline for this one — ”Fear Thy Neighbor” — is a succinct snapshot of our present moment.

If you’ve ever allowed your radio tuner to drift away from your favorite political talk station to listen to what The Other Guys are saying, you have surely concluded that there are lunatics wandering the streets and the corridors of power.

This movie taps in to that paranoid vibe, as nice people who joshed each other on Monday are using each other for target practice on Wednesday. The sheriff, his wife (Radha Mitchell), his deputy (Joe Anderson) and the town doctor, who all keep the town stable and healthy in good times, look on helplessly as their community descends into madness.

The government is behind it, of course, accidentally triggering the outbreak and imposing martial-law containment procedures that only make matters worse. The movie is a nonspecific political parable — you can read it as an indictment of the economic bailout or Tea Party fist-shakers — and that makes it all the stronger. Pick your villain.

But that’s subtext, Romero’s specialty. The main event here is screaming and squirming, and the film is stuffed to bursting with great fright scenes. Eisner directs the film with gritty vigor.

A battle between Sheriff Dutton and the local coroner uses an electric bone saw to terrifying effect. At one point it skitters across the floor toward Dutton as he backpedals on all fours, his crotch exposed to its ravenous circular blade. It’s a nerve-wracking sight gag.

”The Crazies” will have horror fans standing and applauding.