In the first scene of “The Visitor,” Walter Vale struggles in his weekly piano lesson to bend his fingers into the correct position. As his teacher departs, she tells the aging economics professor, “Learning an instrument at your age is difficult, especially if you don’t possess a natural gift for it.” In case the viewer hasn’t grasped the depths of Vale’s despondency by the end of these first few shots, they will soon: in the opening scenes, he gazes forlornly out a window at laughing college coeds, eats at an empty table in a crowded dining hall, and swigs copious amounts of red wine alone in his house.

It’s clear from these initial minutes that director Tom McCarthy’s new movie “The Visitor” isn’t as understated as his last offering, 2004’s critically-acclaimed Sundance hit “The Station Agent.” The story of an introverted dwarf and his cautious friendships was quiet, tender, and moving. These qualities are still present in “The Visitor,” but some of the subtleties are lost behind the movie’s commentary on illegal immigration.

When Vale (Richard Jenkins, “Six Feet Under”) reluctantly travels to a conference in New York City, he enters the apartment he owns (but rarely visits) to find two strangers living there. Illegal immigrants Tarek (Haaz Sleiman, “24”) and his girlfriend Zainab (Danai Gurira) discover that they’ve been renting the place from a scam artist. They agree to leave, but Vale, feeling sympathetic, invites them to stay.

The interactions between Vale and his guests possess both the awkwardness and the warmth that such a situation would invite. As a result, the middle part of the film is the most nuanced and engrossing portion. Though Zainab—a jewelry-maker from Senegal—seems initially cautious and afraid of Vale, Syrian drummer Tarek befriends him quickly and teaches him to play the djembe, an African hand drum. Tarek and his drums fill the void in Vale’s life in a way that his painful piano lessons never could. We discover later that Vale only took up the piano in hopes of connecting to his dead wife, a classical pianist.

The scenes of Vale playing the drums are the strongest in the movie. Tarek introduces him to the music of Afrobeat pioneer Fela Kuti, invites him to jazz clubs, and brings him to play with a group of drummers in Central Park. In these scenes, Vale’s reserved, curmudgeonly self gives way, slowly, to a more expressive man.

Soon, however, Tarek is arrested in the subway and taken to a detention facility. The movie from then on is concerned with the question of whether or not he’ll be deported. As an additional twist, Tarek’s mother Mouna (Hiam Abbass, “Munich”) comes from Michigan to be near her son, although she can’t visit him in jail for fear of being deported herself.

The movie starts to get heavy-handed around the time Mouna arrives at Vale’s apartment. Here the film becomes less about the quiet relationships that develop between characters and more about calling attention to the issue of illegal immigrants. The problem is not that McCarthy’s movie has a message, but that he communicates it in a multitude of tedious ways. When Mouna comments that the detention facility “doesn’t look like a prison,” Vale replies, “I think that’s the point.” In this scene, McCarthy, who also wrote the film, seems to use his characters as little more than mouthpieces.

During one of Vale’s visits to the detention facility, Tarek tells him, “I am not a criminal.” Vale knows it, Mouna knows it, and the audience knows it—but we hear it repeated over and over again. In a way, this illustrates the constant need illegal immigrants feel to justify their presence in the U.S., but the whole bit seems stale by the second time we’ve heard it. It’s the same problem McCarthy has when depicting Vale’s earlier depression in multiple scenes; he presents ideas so repetitiously that they become tiresome.

Two factors save the movie from drowning in social commentary: the acting and the rare moments that subtly speak to the larger picture. Sleiman and Jenkins deliver the strongest performances. As Tarek, Sleiman’s emotional range and huge smile create the movie’s most touching moments, while Vale—brought to life by Jenkins—is the only character given a chance to fully develop. Their relationship is the movie’s best theme and produces nearly every poignant moment. The wordless final scene, in particular, proves that the things left unsaid can still speak volumes—an idea that McCarthy clearly remembers but doesn’t always practice.