More gloppy romantic sap from the Nicholas Sparks tree in this adaptation of the unaccountably popular author’s novel about the love between a soldier and a girl back home derailed by 9/11. Tearjerkers that mingled lost-distance love and combat were hokey when they were made about World War II in the forties; in this day and age, Lasse Hallstrom’s movie seems positively antediluvian. Yet for the mostly female audiences looking for a cheap cry, “Dear John” may prove a welcome, though mawkish, cinematic missive.

Channing Tatum, going for a more realistic portrait of military life than he did in “G.I. Joe,” plays John Tyree, a Charleston native who apparently joined the army after a hell-raising youth. Back home on leave one summer, he meets Savannah Curtis (Amanda Seyfried), a right pretty lass from a less humble background than he. Before long they’re inseparable—except they separate when he goes back to his Special Forces unit, which from what we can see is operating in various locales in Africa and the Middle East, building schools and doing other peace-loving, helpful things for the locals.

John plans to come back to South Carolina, and Savannah of course, after his tour ends, but the attacks of September 11 intervene, and feeling pressure from his unit, he re-enlists and is soon in the thick of combat. And as the title indicates, absence does not make the girl’s heart grow fonder—or at least seems not to, as the title indicates. (Sparks’s idea of layering his narrative is evidenced by the fact that he not only names his hero John, but cleverly chooses a title indicating what kind of epistle he’s going to get from her, too. It’s symptomatic, I’m afraid, of the quality of his writing.)

But our author isn’t content to allow the unhappy course of John and Savannah’s relationship to be his whole story. He adds other elements to increase the maudlin quotient. John’s father (Richard Jenkins) is a preternaturally quiet, reserved, and socially awkward man who apparently suffers—though undiagnosed—from Asperger’s syndrome. And after John recuperates from a battle wound incurred while saving a comrade, he’s called home to the older man’s bedside; he’s had a stroke. (We also get flashbacks that explain, in an almost cruelly saccharine fashion, the elder Mr. Tyree’s obsession with coin collecting—something calculated to support a last-act feel-better plot turn.)

That’s not all. Savannah has a pathetic neighbor, Tim (Henry Thomas—E.T., where have you gone?)—a sad-sack guy whose wife has effectively left him to care for his autistic son Alan (Braeden Reed, then Luke Benward) on his own. Tim’s obviously infatuated with Savannah, and she’s very solicitous about Alan. Also about her horses, to which she introduces the boy. (In fact, she’s so idealistic she wants to start a horse camp for autistic children. You heard that right.) Illness also enters into this story thread.

All this should give you some idea of how incredibly manipulative this film is—along with the pictures made from his other books, it proves that Sparks is the modern Fanny Hurst. Hallstrom, who was once able to transcend potentially bathetic material (as in “What’s Eating Gilbert Grape”) simply succumbs to it here, and he doesn’t help his cast. Tatum overdoes the stolidity; his laconic, solemn shtick is getting tired. And Seyfried makes Savannah even more irritating than the character calls for. Thomas, hidden behind a beard, is pretty much unrecognizable—lucky man. As for that fine actor Jenkins, he actually does a sensitive, nuanced job, which is much more than the material deserves.

Of course, the picture looks nice—pretty locations, slick cinematography (Terry Stacey)—and sounds it too (syrupy score by Deborah Lurie). But as far as “Dear John” is concerned, the best advice is just to mark it “Return to sender.”