Every Sunday this summer, we'll be taking an historical tour of the Hollywood blockbuster by examining an older film that is in some way a spiritual precursor to one of the weekend's wide releases. This week: the evergreen subject of the dully married couple falling back in love because of wacky misadventure gets its latest workout in Hope Springs, in which Meryl Streep and Tommy Lee Jones banter and flirt. Seemed like a good time to revisit one another such star vehicle, starring two people that we'd actually want to see having sex.

"Underrated" always and only means, "I like this more than anyone else I've discussed it with, and to hell with that", and has therefore no real value as a critical judgment. But I still think that Mr. & Mrs. Smith is one of the most underrated popcorn movies of the 2000s, for despite receiving vaguely upbeat reviews, landing in the box office top 10 in 2005, and introducing the Hollywood power couple of the early 21st Century to one another, it has utterly disappeared from every conversation about anything having to do with pop culture or moviegoing or anything else. My only refuge is in the cliché about not arguing with personal taste, because by my lights, this is far and away one of the most entertaining and most successful movie star pictures of its decade; which means an extremely specific thing, it is true, and movie star pictures have long since faded from their glory days of the 1930s, 1940s, and 1950s, to the point where the whole entire idea of a "star vehicle" only makes any kind of sense if the star in question is named Will Smith. But it is no secret that around these parts, those glory days are held in rather considerably higher regard than the '00s, and it is not the smallest charm of Mr. & Mrs. Smith that it marries the narrative sensibility of a '40s production with the preoccupations of contemporary popcorn cinema.

If the concept were any higher, it would need to pack oxygen tanks: Mr. John Smith, played by famous handsome man Brad Pitt, is an assassin, and his wife, Mrs. Jane Smith, played by famous gorgeous woman Angelina Jolie, is an assassin as well, and neither of them know that this is the case; they both think that their partner is a boring, workaday suburbanite. Meanwhile, their arch-suburban existence is slowly killing the both of them with boredom, and their marriage is just about ready to rattle to an end, except their mutual secrets come out and they are obliged to try to kill one another, which makes them fall back in love - and better still, back in lust - and so instead they join forces to kill whoever it is that wants the both of them dead. Nothing of any substance beyond that happens in the film's two hours, and if that sounds like it's not remotely enough incident to fill up that kind of running time, that's because it isn't. Nowhere near it. Plotwise, this is a fucking shambles.

And that's great.

What makes Mr. & Mrs. Smith work like it does - and at the risk of repeating myself with the desperation of a True Believer who can't stand that everybody else doesn't agree with me, there aren't a dozen movies from the whole damn decade that I think work as well in the same register, to the same degree - is that it's not about its plot, even a little bit; it is strictly in the tradition of mainstream film production that once upon a time held that we, the audience, didn't really care what happened or what particular characters it happened to, but only really wanted to watch Cary Grant/Norma Shearer/Jimmy Stewart/Humphrey Bogart/Jean Arthur waltz back and forth onscreen doing the exact same things they did in every single movie. Mr. & Mrs. Smith lives and dies on one single precept: that it is inherently entertaining to watch Brad Pitt and Angelina Jolie fire guns, deliver zingers, and make out. Disagree with even one of these points, let alone all three, and the movie evaporates into a mist of pointlessness, noisiness, and moral ugliness.

After all, 2005 is not 1941, the year of the other major Hollywood Mr. & Mrs. Smith, which was also a screwball comedy about a marriage on the rocks coming back to life anchored almost entirely by the assumption that we like to watch a famous person, Carole Lombard in that case, being all Carole Lombardy (the modern viewer is perhaps more likely to investigate it for being, by a commanding margin, the most uncharacteristic film in Alfred Hitchcock's directorial career - nor, I am afraid, is it terribly successful in that regard). And a screwball film it most certainly is, though disguised by action movie genre trappings: a ridiculously contrived situation that could be resolved in a hundred straightforward ways but where in the hell is the fun in that, and things get more and more complicated and ridiculous before they abruptly stop, and also there is so much sexy, which is a hugely important element of the screwball form that is not, I think, typically given its due respect, I imagine because film scholars want to pretend that it is not totally hot to imagine Cary Grant and Katharine Hepburn boning.

But I was saying, Mr. & Mrs. Smith of 2005 is quite open and guileless about wanting to be a movie that delivers all its intended audience wants of its mindless entertainment: so there are hot actors, large explosions, great big chase scenes, and wave after wave of consequence-free violence, and these things are increasingly difficult to justify. It is totally, irredeemably indulgent, and the only real defense of it on aesthetic grounds is that it's made with a considerable degree of sophistication; Simon Kinberg's screenplay is jam-packed with witty, rather than simply quippy dialogue, that is delivered with flawless precision by the two stars, and under the direction of Doug Liman, who was behind The Bourne Identity and thus did so much to establish the modern face of the action movie while Paul Greengrass gets all the credit, the film's setpieces are awfully hard to fault. Over-edited, maybe, but they are for the most part creative, and the two best ones - one in which the Smiths reduce their posh suburban home to rubble, the other in which they use all the various openings of a minivan to fire at the goons chasing them down the highway - are amusingly pointed in their demolition of the trappings of middle-class ambition.

So let's not defend it on aesthetic grounds: there are movies that only want to be costly, spectacularly dumb entertainments, and while most of these manage only the "spectacularly dumb" half of the equation, and leave "entertainment" somewhere around the second month of pre-production - there are those precious examples of idiotic escapism that are absolutely solid in their craftsmanship and sure in their pacing (and I have always found that Mr & Mrs. Smith screams by as quickly as any action movie of its generation), and so what if they're not great cinema? If there is going to be broad entertainment, I for one would like it to be as deft and charming as it can be, and this film resides in the company of something like the thematically-similar Duplicity from a few years later, a film of almost uniformly shallow appeal that's just really damn good at it.

Which returns us, finally, to Pitt and Jolie, who are the reasons the film works, and is as good or great as it is: Liman's direction crackles and Kinberg's writing pops, but the subsequent work of both those men has been uniformly dreary. Whereas this is, I think, the high water mark of its two stars' careers as movie stars: it is the most perfect summation of the Brad Pitt Character who is laconic, vaguely clumsy but so smoldering hot that you ignore it, and so tightly balanced between smart and dumb that you're not sure which he is; it is also the most perfect summation and indeed the first overt appearance of the Angelina Jolie Character who is flawlessly cool, super-competent, finds everything she does and says awfully amusing, and has a tiny splash of dominatrix in her that gives her extremely present sexual energy a sharp edge to it. More to the point, is the only place where these two characters interact, and while history is littered with backstage lovers who don't spark off any chemistry onscreen, the sensuality that rolls off the screen in Mr. & Mrs. Smith is about as potent as you could find for years in either direction.

This is, in short, a movie about how Pitt and Jolie (that is, their respective personae) are sexy and witty, together and apart; it is shameless about this, so shameless as to seem downright slutty. But there is an ancient piece of filmmaking wisdom, that the secret to making any love story work is casting two people whom most viewers would like to see fucking; and if the following subsequent seven years have been any indication, the thought of these two people fucking has been the primary driving force in America's cultural discourse, which makes Mr. & Mrs. Smith some kind of pornographic masterpiece.