Armando Iannucci's In the Loop is an unbearably funny movie about a subject that isn't by itself funny at all: an act of deliberate collusion between factions within the American and British governments to trump up unsubstantiated evidence from dubious intelligence to drive both of those countries into a meritless war in the Middle East. It is a thinly-veiled look at the run-up to the Iraq War in 2002 and 2003 only insofar as the character names are different, and "Iraq" is never directly identified. Now, ask any of us dirty fucking hippies who were screaming bloody murder about the war back in those days, and we'll tell you that it was not a particularly amusing time to be alive. But Iannucci, bless him, had the same realisation that Stanley Kubrick did when he was making Dr. Strangelove: when something is too absurdly awful to even contemplate realistically, the only way to treat it is as a colossal black joke. And even though the administrations on both sides of the Atlantic have changed over since then, the satire is still sharp as a stiletto; for whenever there are politicians, there will always be people who will happily send the democratic process right into the shitter if it gets them a tiny scrap of power or attention.

Cribbing some characters and a healthy number of actors from Iannucci's beloved BBC comedy series The Thick of It, In the Loop begins when Britain's Secretary of State for International Development, Simon Foster (Tom Hollander), states during a generally terrible radio interview that war is "unforeseeable". Though he seems to think that he's only voicing one man's opinion, his ill-chosen word runs afoul of the official position of the British Government. Which is that war is "foreseeable"? Actually, we never do quite find out what poor Simon ought to have said, but he sets off an epic shitstorm, with the Prime Minister's most able spin doctir, Malcom Tucker (Peter Capaldi), working frantically to make sure that the Americans know that the PM is still definitely behind the war, while a small cabal of anti-war Americans, including Lt. Gen. George Miller (James Gandolfini) and Assistant Secretary of State Karen Clarke (Mimi Kennedy) in their battle against the man in the State Department who seems to be driving everything else, Linton Barwick (David Rasche). Let the record show that this plot summary manages to leave a good half the cast and healthy majority of the story untouched. It's just that kind of movie.

It's hard to decide which element of the script, co-written by the director and a passel of his Thick of It associates, is most praiseworthy: the impossible plausibility of the chain of events it depicts? The you-are-there realism of the politicking on display? Those things are damn good, but you'll have to count me in the increasing swell of reviewers who find themselves just absolutely taken by the film's manic, profane, poetic, logorrheic dialogue. It's really quite extraordinary, how much cumulative imagination the five writers show off in writing an endless panoply of utterly vulgar quips and dry British witticisms; and the even more particular genius of it is that the vulgarity isn't just funny on its own terms (though it assuredly is that, except for those poor souls who are bothered by the inherent fact of the word "fuck"), but that it is used in consistent and distinct ways for each character, defining them as much as their behavior or title. Malcolm is the one with the amazingly colorful and creative euphemisms, Miller is blunt and resigned, Simon's aide Toby (Chris Addison) is sarcastic but generally ingratiating, Barwick is the hypocrite who makes very certain never to say anything R-rated even as he cheerfully imagines sending thousands of soldiers off to fight a war of fuzzy goals.

Naturally, this means that there's a whole lot for the actors to gorge themselves on, and it's worth pointing out that while much of In the Loop works because of the writing, just as much is entirely the credit of the performances. If I had to pick the most effective, I'd probably settle on Capaldi (reprising his Thick of It character), Gandolfini, and Gina McKee (as Simon's more acerbic and honest and therefore unloved senior aide), with honorable mention to the great Steve Coogan (who also worked with Iannucci on the series Knowing Me, Knowing You and I'm Alan Partridge) in a small but truly wonderful role as an angry constituent. But singling out anyone is to miss the forest for the trees; across the board, this is one of the finest casts assembled in a very, very long time, and while only a scant number of them have instant name recognition in the States, that is hardly to say that they're not all gifted in the way that only British TV comic actors can be gifted.

The script; the actors; and then there's Iannucci's direction, which underscores a truth. It is regularly said that a certain kind of film just needs a good screenplay, and a director who can stay out of its way, and that is the best thing; but In the Loop shows that it's really the second-best thing. The best thing is if the director knows exactly how to make the film fairly complex visually and in its editing, in such a way that his directing is itself part of the timing of the jokes. Iannucci puts quite a lot of effort into the look of the film, which uses the clichΓ©d faux-documentary language of handheld cameras and grubby sets as a springboard for something much richer and more carefully assembled. The result is, frankly, one of the most mature and sophisticated film comedies in what feels like many years; certainly, it's one of the funniest, something that withstands comparisons to Dr. Strangelove not just because they have a similar sensibility, but because there's not nearly as much of a gulf separating them, quality-wise, as you might expect. This is as fine and hilarious a political comedy as any we've had in a generation.

And then, at the end, Iannucci pulls the rug out, and it's not so funny anymore, because we realise: oh wait. This happened, kind of. And the war that got put together, probably not in the same farcical way as this, but in the same spirit of lying and power-grabbing, that war is still happening ever day. Thus comedy gives way to raw truth, and it's a powerful, uncomfortable transition, that helps to make In the Loop the best movie yet about the Iraq War, even as it is not in any specific way about that war at all. Which almost revives the question about whether or not there's any real point to an anti-Blair, anti-Bush satire when both of those men are out of power, but I shall reiterate: whip-smart observation and dead-on political analysis are always welcome, season in and season out.