If there’s anything worse than a movie about some trivial subject, it’s a film that trivializes an important one by mishandling it—like “Crossing Over.” The subject is the impact of US immigration and naturalization policy—not only on illegals from Mexico or elsewhere, who have been treated in a great many films, but on those who enter the country legally and then try to remain and assimilate, and on those citizens involved in the implementation of the policy. It’s ambitious—even courageous—of Wayne Kramer to try to deal with so sensitive and significant an issue. But he flubs it by being incredibly heavy-handed and calculating in doing so.

Kramer’s approach is to go the “Traffic”-“Crash” route by intertwining a number of plot lines that intersect at various points. The character who holds everything together is Max Brogan (Harrison Ford), a world-weary INS officer with a heart. When he arrests Mireya Sanchez (Alice Braga) in a raid on a sweat shop, he decides to help with the deported woman’s young son by retrieving him from the place she left him and personally returning him to his grandparents across the border; unfortunately, she’s already taken off to try to get back into the US.

Meanwhile Max’s Iranian-American partner Hamid (Cliff Curtis) introduces him to his family, led by a wealthy expatriate father who, along with Hamid’s hot-headed brother, is furious over the loose life of Hamid’s sister Zahra (Melody Khazae). She’s having an affair with her boss at a copy shop who, in turn, is in the business of forging documents for illegals.

One of his customers is Claire Shepard (Alice Eve), a pretty Australian would-be actress who’s gone over her visitor’s visa and has a romantic relationship with Gavin (Jim Sturgess), a British would-be musician in similar straits. He’s a non-practicing Jew, but has secured a job in a Jewish school so he can seek permanent status on religious grounds.

Claire’s efforts, meanwhile, get her involved with sleazy INS green-card adjuster Cole Frankel (Ray Liotta), who promises to grease the wheels of her application in exchange for sex. He’s married to idealistic immigration lawyer Denise (Ashley Judd), who’s preoccupied with the case of a Nigerian orphan but also gets involved with the of Taslima (Summer Bishil), a Bangladeshi high-schooler who comes under suspicion from Homeland Security when she gives a speech to her class saying that she understands the motivation of the 9/11 highjackers. A hard-nosed agent (Jacqueline Obradors) threatens her entire family—illegals who have resided here for years—with deportation as a result.

Finally, there’s Yong Kim (Justin Chon), a Korean immigrant on the verge of taking the oath of citizenship, who’s forced to join a local gang.

All these threads come together, after a fashion, when Zahra and her boyfriend meet with an unhappy end, Claire’s relationship with Cole is revealed, and Kim learns too late the terrible cost of his gang activities. Meanwhile the fates of Mireya, Taslima and Gavin are disclosed as well. The dramatic set-piece toward the close is a big naturalization ceremony where America’s promise and pitfalls are uneasily juxtaposed.

Kramer’s got a lot of balls in the air here, and on the most basic level he succeeds in keeping them afloat—the various story strands remain clear despite the complexity. And along the way he manages an occasional insightful scene, even an amusing one (a sequence that involves Gavin and a rabbi in an INS office has charm, even if it is a bit sit-commy). But for the most part the approach is so desperately orotund and italicized that the manipulation quotient becomes positively oppressive. The worst example comes near the close in a long dialogue scene between Chon and Curtis, which literally stops the movie dead in its tracks. But there are plenty of other moments when the didacticism is allowed to trump things (every scene involving Judd, for instance). The effect is of cardboard figures being shuffled around a cinematic gameboard, and the fact that the “mysteries” the script uses to keep the plot going have such predictable resolutions doesn’t help at all.

The cast struggles to breathe some reality into the material, but though some—world-weary Ford, likable Sturgess, tense Bishil—elevate their scenes so that they actually approach authenticity, most deliver nothing more than journeyman turns, and some (Judd and Liotta in particular) overdo things badly. Technically the picture is adequate, though it has no particular style.

This is a subject that could be the stuff of pointed drama. But the lack of subtlety here makes “Crossing Over” little more than an overwrought harangue.