Director Joshua Marston began his career in TV journalism, and somehow that feels exactly right. Not one of his films have been a documentary, and not one of them have had anything like a documentary aesthetic, but they have do have one important element of great journalism: they observe. The filmmaker's approach is long on quietly watching characters go about and behave, short on making any conclusions about that or judging them; his films are simply opportunities to watch people dealing with what life throws at them. This was true of his 2004 debut Maria Full of Grace (which silently remains one of the best films of the 2000s that everybody has completely forgotten about), and it's equally true of his fourth feature, Come Sunday. Even truer, maybe - Come Sunday takes as its subject the social mores of conservative American Evangelical Christians, and proceeds to not have anything particularly mean or superior to say about such people. Which I suppose might be the kind of thing that somebody, somewhere might consider to be irresponsible or some such, and yet in practice, it's mostly just terrific, seeing how social interactions unwind in a very particular, high-stakes social environment, and letting that be what's interesting, not scoring rhetorical points.

The film is a biopic of Carlton Pearson (Chiwetel Ejiofor), a nationally significant minister at an Oklahoma megachurch, and a personal mentee of Pentecostal televangelist Oral Roberts (Martin Sheen). In the early 2000s, Pearson found himself at a crossroads: his life of preaching - very sincere preaching - had centered on fundamentalist convictions about the need for absolute commitment to his particular branch of conservative Christianity in order to be saved from an eternity in Hell. But a combination of his personal moral observations, and what he firmly believed to be God's words of guidance, led him to begin preaching a new "Gospel of Inclusion", maintaining that all humans, regardless of their beliefs or behaviors, will ultimately be reconciled with God. By 2004 Pearson's church had largely collapsed and he had been denounced as a heretic.

Come Sunday watches with detached sympathy as all of this plays out, taking a stance towards religion that recalls in intention (if not in execution) some of the great religion-themed European art films of the 1950s and 1960s. Namely, it considers that a crisis of faith is one of the most difficult, consequential experiences that a believer will ever experience, and it stands back with some respectful awe as Pearson is put through his paces. There's a plot here, but it's kind of a shapeless, piecemeal thing; after all, there are only so many variations on "what you believe is contrary to all we believe and we'd like you to stop it". Instead, it's an almost purely psychological arc. We know, from pretty early on, that Pearson won't recant and that this will cost him dearly; the purpose of Come Sunday, then, is to examine in some detail how he copes with this.

It's a film that cannot function in the absence of a strong central performance, and it sure as hell has that: I joined Team Ejiofor in 2003 and have never wavered off it it even slightly in the 15 years since, and this still might be my favorite performance he's ever given in a movie. It's already impressive enough that he's able to cope with a conflict and dramatic shape that is almost entirely internal; it's more impressive still that he's able to handle the complication of playing a character of extreme, deeply-held religious beliefs, and make us understand the ripping apart of his very heart and soul that comes from the fear that he may be letting down his God and not just his friends and colleagues. That's a teeny-tiny needle to thread, and I'm not sure that I've seen a non-Scandinavian actor do such great work with this precise character type, wearing in his strained facial expressions (Ejiofor looks startlingly old and tired here) and in his closed-off body language a truly profound conflict of the mind and spirit. On top of all of which, he's also drawing out the idea that, as a Charismatic preacher almost must be, Pearson's got a pretty strong ego problem that cuts against his religious fervor and anguished soul-searching

Ejiofor makes the movie worth seeing, full stop. Nothing else I could say against Come Sunday should detract from that. And it's not that the film is otherwise "bad"; it's not really that the film is otherwise much of anything at all. That thing I mentioned, that there are only so many variations on the central dramatic concept that can be explored? Well, Marcus Hinchey's script explores the hell out of them, and it's not above repeating itself. The idea, I'm sure, is that every repetition gains nuances from the slow shifts of Pearson's feelings about the situation, and Ejiofor goes at least a little bit of the distance with that, but the script affords the supporting characters no such dignity, and while Pearson evolves in very small, interesting ways across the film, the people around him just keep running the same routines over and over, like a non-player character in a video game who won't stop saying the same line no matter how many times you talk to them.

The supporting characters really are the problem here, I think. They're repetitive, they have limited inner lives, they're boring - and they're distracting. The film has only a few major characters, and they're disproportionately played by people who are easy to recognise: only Condola Rashad, as Pearson's non-religious wife, was wholly unknown to me among the more-or-less "leads". Sheen, of course, is Sheen; Danny Glover is on hand to provide a well-acted but thoroughly unbalancing cameo as Pearson's dissolute, imprisoned uncle, who kills himself when Pearson refuses to intercede with the the authorities on behalf of an unrepentant sinner. The biggest part after Ejiofor's is his business partner, Henry, played by Jason Segel, in a sullen, morally-wracked role that almost reads as stunt casting. Which leaves us with only Reggie, the self-loathing gay choir director whose religion has kept him locked in the closet as his health deteriorates due to what is heavily implied to be an HIV-related illness; Lakeith Stanfield plays the role with terrific jolts of nervous energy, providing the clearest character in the film after Pearson himself, and turning a strong monologue into even stronger dialogues.

Come Sunday's vague structure and vague characters harm it, but they don't ruin it: the foundation is too strong for that. Ejiofor's Pearson deserves a stronger film, but in the absence of that, the comfortably mediocre one he gets still passes the time readily enough as his performance silently detonates. It's middlebrow as anything, but worse middlebrow stuff comes out all the time, and at least it's the kind of middlebrow thing that makes demands of its viewer.