Nicolas Cage’s arms-dealing hero of “Lord of War” compares selling his first gun to losing his virginity. If only the movie left the viewer as excited or satisfied.

Making a movie about the flaws of global arms trade is certainly a laudable idea in theory, but the film’s heavy-handed morality is bogged down by underdeveloped characterizations and a plot predictable to the pinch. (And, maybe worst of all, that forlorn expression is cemented upon Cage for yet another big budget movie.) But at its best moments, especially its bookends, “Lord of War” takes advantage of dramatic visuals to send home its didactic but sporadically interesting message.

The film opens promisingly: a camera follows a single bullet from the factory assembly line to a Russian officer, to guerrilla troops in Africa, to the head of an unsuspecting African boy. The message? Selling guns to war-torn developing countries is an irresponsible way of making the wealthy wealthier, with shocking consequences for everyone else.

That lecture is delivered unapologetically from there on in. Cage (Yuri Orlov) stands amidst a smoldering war zone in a decrepit town, looks directly at the camera, and delivers compelling worldwide arms statistics. (There is a gun for every 12 people on the planet; there are more gun shops in the United States than McDonald’s; the five permanent members of the U.N. Security Council are the world’s biggest arms suppliers.)

Too bad these statistics are among the most moving aspects of the film.

He may have good intentions, but writer-director Andrew Niccol poorly executes his convictions. Despite the movie’s solid cast, Niccol completely fails to create believable characters, without which the film’s plot and haughty themes flounder.

Cage is almost too easy a target. Orlov lives in Little Odessa, N.Y., and apparently joins the arms trade because he’s bored and wants to make something of himself. Watching him turn from an insecure, unaccomplished young man into a conscience-less warlord is neither gripping nor convincing.

Orlov claims that he doesn’t do it for the money, but instead: “It’s the only thing I’m good at.” His voiceover narration is supposed to make him more sympathetic to the viewer, but instead he comes off as detached and confused. While he says he has a knack for languages and speaks many in the film, Cage’s attempts at communication are woeful to behold.

He is barely good enough to play the bad guy action-hero (“Face Off”), and the lackluster dialogue leaves the actor with a flatness that can be excruciating.

Things aren’t much better for the supporting cast. Orlov’s brother, Vitaly (Jared Leto) helps with the arms-dealing, but mostly hangs around the film coked-out. (That he developed an addiction in two days is an example of the film’s utter failure to deal with character development).

Using profits from their business, Orlov tricks a model (Bridget Moynahan) into falling in love with him. Five minutes into their relationship they’re engaged (an agreement that is just slightly more stupid than the one Cage hooks in “The Rock.”) The poor brunette doesn’t know anything about his arms dealing until the end, and so her role in the film is little more than banal and superficial.

Ethan Hawke is tragically under-used. Playing an Interpol cop, he chases Orlov throughout the film, gradually getting closer and closer. His repeated appearances are without any substance — or, much more importantly, action.

Niccol flaunts his knowledge of the international arms trade, but seems to have put little energy into flexing any of the muscles of filmmaking. At a running time of two hours and six minutes, the film just can’t afford the flimsiness of its story-line. Who could have guessed that Orlov would amass great wealth and power, only to lose everything he cared about in the process?

Perhaps the biggest culprit are stinging one-liners that hover between the inane and cliched. While Orlov woos his model, she asks him: “Doesn’t this feel like fate?” Before kissing her, he replies: “I don’t believe in fate.”

What the film lacks in plot, characterization, or dialogue, it begins to make up for with amazing visual juxtapositions. When Orlov buys a huge stock of Soviet arms right after the Cold War, he sits on top of a fallen statue of Lenin. Then when wind blows his money out from his hands, Orlov leaps in a fury to gather his cash while children are shot by his guns on the other side of the wall.

Later in the film, in a different but equally effective moment, Orlov watches a Muslim fundamentalist fire his weapons, while the sound changes quietly from gunshots to a cash register’s ring.

Orlov repeatedly insists that the genocidal carnage his guns cause “is not our fight.” Evidently, this is Niccol’s way of insisting the exact opposite. How could he possibly have hoped to get that message across with such an static, passionless piece of entertainment?