If The Visitor is the best that liberal filmmaking has to offer, the right wing populism implicit in so many Hollywood features has nothing to fear. It’s a shame, because Tom McCarthy’s new film (he also directed the sweet and subtle The Station Agent) seemingly has a lot to recommend it, on paper at least.

It’s the tale of an uptight academic widower, a specialist in international affairs, whose life is transformed when he encounters a Muslim couple. Were this a Tony Scott film, the transformation would be because they get him to swear allegiance to Allah after tying him up and dunking him in oil (politics, see?). But no, this is all about the slow alchemy that occurs when the academic is brought out of his shell by the erotic rhythms of a djembe drum.

The djembe is played by the male Syrian half of the Muslim couple, who are in America illegally as far as the authorities are concerned, and who turn up just at the moment you expect them to in the film. Which is one of its problems: I was a minute or five ahead of all of the film’s turning points, except the bit when a hovercraft full of liberal mavericks turned up to bust the Muslims out of their corporately owned detention centre. Turns out that was the ten minutes of the film I was asleep for, but damn if it wasn’t the most exciting part of the whole thing.

Actually, the corporately owned detention centre had cropped up before I nodded off, and it was one of the more effective aspects of the film. Sadly though, this is a film that has its heart in the right place, but thinks too small. An ageing academic is loosened up by his contact with a brown skinned percussionist, and the American government intervene to spare him the problem of having a houseguest outstay his welcome. That’s pretty much it. OK, at least we’re spared the big budget version of the story, where he quits his academic post and goes on the road with a Santana cover band populated by quirky seniors (The Bucket List meets School of Rock: I can see it happening, what with the lure of the grey dollar…). But it seriously would have helped the script (also written by McCarthy) for some more imagination and a sense of the epic to be brought into play.

What ultimately failed to convince me about The Visitor was its commitment to liberal politics instead of messy human realities. The academic is not attracted to the djembe player’s wife. The Muslim couple do not exploit his friendship. The academic’s field of study is international affairs, which far too neatly mirrors the film’s concerns. And so on. It’s not that there’s anything wrong with the choices made, just that together they’re too obvious a selection. Result? A film that will only ever preach to the converted. Great for making white liberals feel better about themselves, and that they too might one day play drums with an exotic refugee, but in every other respect a film that consistently pulls short of really engaging your emotions because of the safety of the choices made at every step of the filmmaking process.