With "Dear John," Channing Tatum imparts a performance of startling vulnerability. It's an emotion previously unseen from the actor, who mostly gravitates to roles that require intense amounts of pouting, Gap-ad posing, and B-boy grunts. It's Channing's newfound sense of soulful release that helps the sudser "Dear John" locate a special footing to work with, heading into the manipulative universe of author Nicholas Sparks armed with a somewhat settled, organic mood of emotional response to best repel the onion-peeling shamelessness of the whole endeavor.

On leave from military duty, John Tyree (Channing Tatum) has returned home to check up on his distant, ritualistic father (Richard Jenkins), also spending time riding the ocean waves. At the beach, John meets college student Savannah (Amanda Seyfried), and the two strike up an immediate romance with only two weeks to bloom. Swearing to each other they'll continue the relationship through letters, John and Savannah pour their hearts into their correspondence as John heads into dangerous territory and Savannah finishes school. Spending a year making plans for a future together, the romance is threatened when the 9/11 terrorist attacks trigger further military duty for John, pulling him away from his true love.

With Sparks, there's going to be schmaltz. The author of the "The Notebook," "Message in a Bottle," and "Nights in Rodanthe" is notorious for his taste in romantic tragedy, which has gifted him a legion of devoted fans, but only a mediocre multiplex output. It takes a highly trained director to tame Sparks for the screen, and "Dear John" has a veteran in Lasse Hallstrom, helmer of "Chocolat" and "The Cider House Rules." Hallstrom knows his way around heartbreak and domestic frigidity, and his syrup whispering skills come in handy, as "Dear John" has a tendency to buck wildly when it comes to articulating the strain of a long-distance relationship.

Make no mistake, "Dear John" exploits every last opportunity it can for tears and swoon, but Jamie Linden's compelling script remains respectful to the characters and their quandaries, building a plausible connection between John and Savannah that Hallstrom spends the rest of the movie dismantling. Linden does a superb job of adaptation, able to convey a sense of ensemble and distraction for the two lead characters without popping their bubble of intimacy. "Dear John" is not only interested in romantic moods, but also takes on the trials of military duty and touches on the mysteries of autism, viewed through the Jenkins character, who's shut out his son for the comfort of routine and the nuances of his coin collection. While a few jagged edges remain (Henry Thomas plays a baffling third wheel character that factors into the plot in a major way, but never quite earns his importance), the storytelling is remarkably crisp and inviting, only giving into repellent histrionics on a few clunky occasions. Thankfully, Hallstrom prefers the slow burn of introspection, relying on looks and body language to communicate so much about these characters.

Hallstrom also pulls some worthwhile acting out of Channing, which is true directorial heroism. Dialing down his crude bravado routine, Channing finds an appropriately unsettled mediation for John; he's a blunt weapon finally finding purpose with Savannah, who returns his affection and helps the character to appreciate his father's delicate psychological situation. Channing still has trouble smothering his indication problems (jaw-clenching to this guy is like lip-biting for Kristen Stewart), but it's an open-wound performance that meshes wonderfully with the sentimental nature of the story. Seyfried is a fine partner, though she gets too carried away in the melodrama. Still, the characters communicate a believable bond that's put to the ultimate test when life makes other plans for their idealized future together.

The sloppy, suspiciously convenient hand of Sparksian fate crashes into the final act, damaging the film's friendly demeanor with a series of operatic plot turns that range from genuinely endearing (John and his father share a lovely moment of direct communication) to instant dismissal. Hallstrom does what he can to preserve the mood, but "Dear John" limps to a conclusion when the genre typically demands a sniffly knockout punch. It's disappointing, but the mere fact that "Dear John" works at all is cause for celebration.