Every now and then, the curious in-between state of being a film critic in two different countries means an occasional slip in awareness. As much as I try to stay abreast of both the UK and US release schedules, I’m sometimes surprised to find that this film or that has or hasn’t surfaced in one of those regions — particularly when the parallel universe of the festival circuit means so many things are seen out of time.

Which is why this post arrives a fortnight late: somewhere between my festival exploits in Edinburgh and Karlovy Vary, I completely failed to register that Sarah Polley’s “Take This Waltz” — itself a long-tarrying premiere at Toronto last autumn — opened Stateside at the end of June. (Perhaps I was distracted by its August release date in the UK.) No harm, no foul — except when we’re talking about one of the year’s best films.

Since being acquired by Magnolia at Toronto — where reactions ranged from the ecstatic to the exasperated, proving once more why films shouldn’t be evaluated by aggregate website scores — fans and sceptics alike have wondered why the distributor held Polley’s beguilingly modest character drama back until mid-summer, a release patch where even the strongest counterprogramming strategy is vulnerable, and, without a full armada of critics backing it, its award-caliber performances and construction seem least likely to gain the industry foothold they deserve.

But watch the film itself, and the scheduling makes pleasingly content-sensitive sense. The phrase “summer movie” has come to imply any form of effects-laden tentpole blockbusters, but taken at its most literal, it’s hard to think of a film that embodies the season with more tactile specificity than “Take This Waltz,” an ostensibly interior film in which adult relationships nonetheless brew, bend and buckle in the salty grip of the sun.

None of the principals in its itchy, untenable love triangle may realize or acknowledge it, but this is not a story that would unfold, or even end, in the same way over a winter, or even a cool-headed spring. Summer loving, as two overage teens once sang, happens so fast, and the humidly hovering air and sticky Toronto pavements so lovingly evoked by Polley in her jambalaya-colored film amount to more than 93-degree atmospherics — they’re behavioral catalysts in and of themselves.

It’s that ripe environmental awareness that makes emotional sense of a film both narratively spare and sensually cluttered, even when Polley’s writing tilts toward the affected: in a story that hinges on irrationally ruled desire, every mood-influencing detail, be it the saturated color of a sweat-stained T-shirt or the near-palpable aroma of chicken cacciatore, goes beyond the decorative and into the realm of consequence. If filmmaking is chiefly a sensory exercise, this represents a quantum leap from Polley’s already encouraging debut “Away From Her” — less cautiously tasteful in its design, more unruly in its emotions, the work of a young filmmaker who has discovered that grown-ups aren’t as grown-up as we think they are. That it’s as unapologetically sexy a film as North America has produced in many a year, doused in the hot stink and brute poetry of intercourse, is hardly incidental to its merits, either.

That doesn’t immediately appear to be the case. It’s rare that a film this wonderful overrides a red flag as glaring as an opening-act speech by Michelle Williams’s diffident protagonist Margot, in which she muses to an airplane seatmate about her fear of “connections” — she’s talking about connecting flights, but it doesn’t take even a glancing interest in psychology to tell that she isn’t, not really, and for a good few minutes, we have every reason to fear two further hours in the company of a transparent mouthpiece for all manner of twentysomething neuroses.

But then something interesting happens: just as said seatmate, who just happens to be her unwitting next-door neighbor and future lover Daniel (the highly promising Luke Kirby), calls Margot on her and the script’s cod self-analysis, so does the film. The faintly teeth-gritting talk of connections emerges as clever lampshading of a boldly selfish character better at observing her problems from a distance than taking possession of them, whose passive preference for emotional limbo is what leads her so casually into adultery.

Peacefully married to the avuncular Lou (Seth Rogen), an aspiring cookbook writer whose patience with her moods is more detrimental to the relationship than one might think, she takes no more responsibility for this happiness than she does for her undirected yearnings: she appears to have walked into marriage as unquestioningly as she has into infidelity. Played with customary intuition and soft-fruit sensitivity by Williams, that may make her a maddening character, but not an unbelievable and unsympathetic one. 

As her characters play-act at adulthood in their brightly painted slatted dollhouses, Polley appears to be nagging at why their domestic structures don’t wield the weight of permanence or formality they did — or merely seemed to — for older generations. Grumpier viewers have complained about the feyness of the supposed hipster community in which Polley has set her otherwise classical femme infidèle study — she’s a drifting freelance copywriter, while Daniel, in a touch particularly aggravating to the film’s detractors, is rickshaw-runner — but in this not-wholly-naturalistic drama, the preciousness of these lives seems a valid subject for scrutiny, not just a scriptwriter’s twee fancy. How do middle-class adult live lives this unreal? Some critics are asking this question, but so, to some degree, is “Take This Waltz.” 

Abetted by its meticulously color-coded cinematography and costume design, part and parcel of the film’s fevered summer sense, “Take This Waltz” is the unusual kitchen-sink drama that plays with woozy distortion of reality rather than effortful amplification of same. Its finest moments are one that actively wallow in fantasy. An exquisitely written and delivered mid-film monologue for Daniel, detailing in unflinching carnal detail precisely what he’d do to Margot were she his, is an elevated writer’s flourish as triumphant as the aforementioned “connections” solo is uncertain; arousing some audible whimpers at the press screening I attended, it’s as erotic a scene as has ever been achieved in film without the removal of one stitch of clothing.

A similarly frank sequence, and Polley’s grandest directorial coup, comes late in the film, as a swirling, circling time-lapse shot, scored to the ashily plaintive Leonard Cohen ballad of the title, details Margot and Daniel’s full sexual courtship, from tentative acquaintance to extravagant perversion to banal domestic interaction — it’s a remarkable bridging of the most  heightened and the most mundane polarities of human desire. Popular music is ingeniously used throughout: the bubblegum absurdity of one indelible 1980s one-hit wonder, in particular, cruelly augments and finally counters Margot’s most damagingly escapist instincts.

Williams has such form in negotiating intelligently tricky, ungiving young women on screen that it seems she’s no longer capable of surprising, but she does so here anyway. It’s the sexual restlessness that feels new and invigorating in this performance, beautifully balanced by the never-better and, crucially, never-stiller Rogen, shorn of schtick here and exposing warm reserves of feeling. (It’s the superb Sarah Silverman, by contrast, who gets to act out as Lou’s abrasive, involuntarily perceptive alcoholic sister.)

It takes actors of rare grace and empathy to make filmmaking this intricately formed breathe and bleed: on the page and behind the camera, Polley dares to risk over-designing here and there, confident in the human core of her story to see her more lavish ideas through. That and the steaming sun, at any rate. Good on Magnolia for waiting to give us the year’s truest summer movie.

‘Take This Waltz’ is currently in theaters. Already seen it? Share your thoughts in the comments below.

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