The most overwhelming takeaway from Private Life is that Tamara Jenkins needs to be enabled to make more movies. In a career stretching 20 years, the writer-director has only now made her third feature, following Slums of Beverly Hills in 1998 and The Savages in 2007, and once again she's created an immaculate gem of modest filmmaking and plotting hiding exemplary human-scale writing and performance. This time around, the lead actors giving career-peak work are Kathryn Hahn and Paul Giamatti in the roles of Rachel Biegler and Richard Grimes, a married pair of upper-middle-class New York creative types who are dealing with their 40s in an unbelievably stupid way: they are sinking all of their energy and more than all of their money into fertility treatments, adoption agencies, and anything else that will end with them being the parents of a newborn child.

By using the phrase "unbelievably stupid", I have already exhibited more moral judgment towards the characters than Jenkins, which is part of why she's a genius. Within Private Life - a semi-ironic title, given that the central couple is doing so much to vomit their privacy up into the public eye; but also, we are being allowed into their marriage with impeccable intimacy - there is no attempt to belittle Rachel and Richard, though they are made the butt of jokes, some of them mean. There is, instead, simple observation, generously allowing the characters to do what they will and always responding by acknowledging that they couldn't fuck up that badly if they weren't normal people with nervousness and hopes and fears getting the better of them just like the rest of us. In a year that produced far more than its share of great cinema, I really do find myself at a loss to think of one film from 2018 with more finely-drawn humans in its script.

Nor, potentially, one with a more perfectly-matched pair of leads. Hahn and Giamatti have the cadences of a long-in-the-tooth marriage down pat: the way that individual gestures can stand in for entire conversations, the oscillation between comfort and boredom that both seem slightly tinted by irritation no matter how happy they are. Hahn gets the edge by virtue of the film directing its sympathies more towards her (as the member of the partnership who would actually become pregnant, she gets to be more righteously indignant), but this really is such a fine matched set of performances. One early moment that could serve to describe a whole lot of things that are brilliant about the film will do: early one, as they prepare their apartment for the arrival of a social worker, Rachel and Richard fret about what to do with the explicit, though not graphic, vagina-oriented painting of a woman hanging in their living room. Rachel storms into frame, wearing no pants herself, and beneath the unbelabored comedy of the moment, we learn so much about this marriage from how well Hahn doesn't reveal any knowledge of being half-naked, moving her body in a completely unselfconscious way, and how Giamatti's reactions don't feel like an actor having the respect not to stare at another actor's crotch, but a husband who's no longer astonished by the sight of his wife's genitals, and doesn't really register what's going on.

Private Life will not go on to be a film about how this marriage is torturing these characters, nor on the small petty wounds these two people inflict on each other. Despite a couple of shouting matches, there's no real sense that any of this is hurtling towards divorce. And that's already a pretty shocking novelty for a character comedy-drama about an old marriage. Instead, it's mostly about two people - educated, writer types, living in an obviously pricey condo that is decorated with a note-perfect mixture of class-defined taste and actual personality - who decided at one point that the wanted something but crucially did not decide why they wanted it, and how they have formed a codependent spiral as they obsess more and more over getting it. That said, it's not as blunt as the addiction drama implied by multiple characters in dialogue. It's more like a tragicomedy of being insufficiently self-reflective, and so making obviously wrong decisions because you've gotten to used to only thinking one step ahead.

It's not nearly as heavy as that sounds. Jenkins's screenplay is full of crisp dialogue that's not quite full of quips and one-liners; snappy, funny banter that feels a bit too fully-articulated to not be jokes, except then when the couple is visited by Richard's brother's step-daughter Sadie (Kayli Carter), her enthusiastic way of talking over herself throws into relief how much of the main characters' smooth dialogue is part of their cozily bunkered New York literati lifestyle. Even when it gets bleak, the film has a sense of humor: a very awful Thanksgiving dinner ends with Richard's sister-in-law Cynthia (Molly Shannon) screaming at him and Rachel while they scramble into a car, as her husband, his brother Charlie (John Michael Higgins) spouts cheerful boilerplate farewells as he shoves leftovers through their window. Small little human grace notes like that litter the movie.

The characters and what happens to them and what they do get all of the attention, but as she did in The Savages - a movie I think about as often as any other 2007 release - Jenkins proves that she has a pretty remarkable sense of what to do with the camera; it's just not showy, and it's always there to support the script. The film makes Rachel and Richard's condo into a chain of boxes, sometimes shot to maximise the squareness and flatness, pinning the characters inside of their cluttered stuff like dead animals in a natural history museum (the vagina scene is a great example), sometimes using sudden depth to let us see how all the space fits together and how the characters are both separated from each other but also fundamentally tied. There are a few compositions that, simply by approaching a room from a diagonal, suddenly reveal the unspoken discord between the couple; there are two scenes where the film jumps over the all-important 180-degree line, and it so perfectly reinforces the lack of connection between the characters each time that I have chosen to believe it was not an accident.

The sets themselves are perfect little dioramas, manicured spaces that give Jenkins plenty of opportunities to push the characters around, and that give the actors plenty of things to interact with. In a film that is primarily about dealing with frustration by doubling-down on the things that feed it, the amount of business the characters have to do becomes a critical part of how we get inside their defensive heads; sometimes, as simple a thing as showing one of the characters freezing hits like a thunderbolt. Rachel and Richard are good at communicating but terrible at expressing themselves, and so Jenkins and Private Life must do it for them; the result is a portrait of middle-aged desperation that is restrained and sprawling in equal measure, and a simply beautiful human comedy.