Absence just makes this flick grow duller

Channing Tatum as John, Amanda Seyfried as Savannah, soldier boy and college girl who enjoy passion, turn to pen and paper.

In the reliably moist novels of Nicholas Sparks - The Notebook and Message in a Bottle - life is a beach, love shifts like a sand castle in a storm, and lovers don't know what they've got till it's gone.

So it is in Dear John, based on Sparks' book, in which a college girl, Savannah (Amanda Seyfried), and a soldier boy, John (Channing Tatum), meet on a Carolina pier during her Easter break and his furlough in the spring of 2001. They enjoy two passionate weeks before returning for active duty.

While John is billeted in top-secret military zones, they exchange letters about life after his tour of duty ends. But what will happen to the lovers when a certain event in September 2001 rocks the world?

Compelling premise, good director (Lasse Hallström), two solid performances from immensely attractive and sensitive leads. So why does Dear John, which begins promisingly, dwindle instead of build, as if focused on the wrong end of the hourglass?

My best guess is that reading the letters in a book is more emotionally powerful than hearing the actors' voice-overs, illustrated with images of them in dorm room and bunker. Hallström fails to visually connect them when they are separated.

Split-screen shots of them joined though distant, or flashbacks to their time together, might have been schmaltzy, but they would have visually underlined the connection despite separation. When Tatum and Seyfried no longer share the screen, generating heat, the movie grows as cold and lumpy as yesterday's she-crab soup.

The film has two curious subplots and supporting performances that feel tacked on rather than organically part of it.

Autism is to Dear John what Alzheimer's was to The Notebook: an impediment to the lovers' connection (as if distance weren't enough). And also a condition to which one of the characters is dedicated to improving.

John's father, played by Richard Jenkins, is a socially phobic man. Savannah suggests to John that his father may be mildly autistic. She knows a little about autism as the son of her neighbor, Tim (Henry Thomas), is diagnosed with it.

War. Duty. Long-distance loves. Socially challenged friends and family members. You watch Dear John and you stop thinking characters and start thinking plot mechanics. What's the next hurdle Sparks will place on the obstacle course of his true lovers?

Contact movie critic Carrie Rickey at 215-854-5402 or crickey@phillnews.com. Read her blog, "Flickgrrl," at http://www.philly.com/philly/blogs/flickgrrl/

Dear John

Directed by Lasse Hallström. With Leslea Fisher, Henry Thomas, Cullen Moss, Scott Porter, June Letourneau, Michael Harding, Richard Jenkins, Amanda Seyfried, Mary Rachel Dudley, Channing Tatum. Distributed by Screen Gems/Sony Pictures.

Running time: 1 hours, 48 minutes.

Parent's guide: PG-13 (for some sensuality and violence).