With spring on our doorstep, the cinematic year of 2009 also begins in earnest. One of its first promising offerings is the festival-friendly romantic drama “Two Lovers.”

Leonard Kraditor (Joaquin Phoenix), his fiancée having recently left him, stands on the precipice of depression and suicide before he is introduced to Sandra (Vinessa Shaw), the daughter of a family friend. The adoring Sandra cajoles Leonard from the clutches of melancholy and the two soon become an apparently happy couple.

That is, until Leonard meets Michelle (Gwyneth Paltrow), his sultry new neighbor from across the courtyard. Although Michelle is already the mistress of a wealthy midtown lawyer, Leonard casts himself into blind obsession, which threatens not only his blooming relationship with Sandra, but also his already precarious will to live.

Phoenix is currently more infamous for his recent talk-show antics and devil-may-care unkemptness than he is lauded for what was once a prodigious acting career. This reality is made all the more ironic given his praiseworthy turn in “Two Lovers.”

Phoenix navigates his character’s labyrinthine psyche with masterful touch, molding and remolding Leonard’s tortuous internality from burdensome grief, to windless composure, to unchecked elation and back again.

Leonard’s rueful naiveté and mislaid hopes are made all the more punishing in Phoenix’s capable hands.

Despite his bizarre, now self-parodying lifestyle, his performance in “Two Lovers” serves as a reminder that, should Phoenix indeed leave acting for good, we will all have lost one of cinema’s finest young talents.

Paltrow continues her streak of fine turns with an alluring, slyly tempestuous performance. Covetous, elusive and imposingly sexual, Paltrow effloresces with a brassy sensuality that couples with a subtle yet discernable inner discord to cultivate a rich and enigmatic character.

Shaw is also to be commended. Though she appears on screen fewer than a dozen times and is given less substantive dialogue, she manipulates her vastly underwritten character into a lively, flesh-and-blood protagonist of nearly unbearable sympathy.

Relative newcomer James Gray is to be commended both as the film’s writer and director. His lensing is silent and unassuming, a palatable visual rendering that lives in and among the characters, turning the pages of the story in a muffled hush.

Gray’s screenplay, co-written with Ric Menello, is the picture’s unshakeable foundation. His ill-fated love triangle and the duplicitous, self-deceiving characters which cement it make for an agonizingly convincing post-Shakespearean romance.

However, Gray’s script is also what most encumbers his film’s would-be ascent to greater, more memorable heights.

The opening 15-to-20 minutes of the film are exasperatingly slow. It’s not until well after the sordid two-facedness of Michelle’s character is unsheathed that the story garners its intrigue.

Until then, the film stumbles along in a cumbersome and fruitless effort to provide the back-story and character development necessary for its later and more gripping dilemmas.

Above all, Gray’s screenplay is, at times, criminally melodramatic. The early stages of Leonard’s dualistic courting are fraught with the ineffectual pseudo-swooning schmaltz you’d expect from daytime television.

Though the foreplay soon gives way to a touching, almost palpable romantic drama, Gray would have done well to ripen his characters’ courtships beyond the shortcuts and clichés of lesser moviemaking.

Still, there’s something tender even amidst the melodrama. Leonard’s story, at first seeming overwrought and unbelievable, matures into something accessible – something painfully tragic and real.

The conflict which rages inside Leonard – to be engulfed by his infatuation for Michelle or to have the courage to love Sandra as she deserves – is an impasse faced by so many, an impasse which so often proves invincible.

“Two Lovers” is an engrossing, superbly acted romantic drama which, for all its melodramatic detours, ultimately besets itself on a path illuminating the redemptive potential of loss and the many perils of a mania mistaken for love.