Hard though it may be to recall, there was a time when U2 were a force on the make, and not the Compu-Global-Hyper-Meganet, iPod-schilling-uber-brand they are today. And that time was somewhere in the order of just over 20 years ago, when U2 stood on the cusp of the release of the record that would irrevocably change their future, and no less the future of rock music: The Joshua Tree. 20 years, and yet no relief from writer’s puns on I Still Haven’t Found What I’m Looking For.

By the time of the Joshua Tree – the band’s fifth studio album – U2 had already traded the Joy Division inspired, post punk leanings of Boy for the new wave spiritualism of October. Moved on to the bracing, militaristic straight edge of War and had achieved global success with its agitprop singles – œSunday Bloody Sunday’ and – œNew Years Day’. Still that was discarded for the wilfully out of focus, European stylings of The Unforgettable Fire, which had teamed the band with the production duo of Brian Eno and Daniel Lanois – who branded U2 with the darker atmospherics which still inform their sound today.

With Eno and Lanois, U2 refined their uncanny ability to marry the cinematically epic soundscape with the inwardly questing lyrical couplet. Case in point, opening track Where the Streets Have No Name. Having survived Eno’s famed attempt at erasing the master tapes when the song’s two different time signatures could not be reconciled, Streets remains one of U2’s most rousing live staples. It stamped their anthemic blueprint, which has so often been ripped off since – not least by U2 themselves on their most recent releases. But this initial conjuring of some mythic, unknowable space remains Bono’s most potent, with the band beneath him delivering it via driving snares and Edge’s shimmering, multi-layered delays.

The Joshua Tree marked the start of U2’s – and particularly Bono’s – ongoing love affair with America. Points of reference on the album for him were mostly literary: Norman Mailer and the new journalism; Salman Rushdie’s Central American odyssey, The Jaguar’s Smile; the Southern Gothic of Tennessee Williams. These influences came to bear on brooding tracks like Exit and its narrative stalking the trail of a killer on the lam, and the searing invective of Bullet the Blue Sky, which chronicled Bono’s post-Live Aid travels through El Salvador.

Though it explored the personal in a particularly naked way, Bono’s songwriting on the Joshua Tree did not annex the political. Take Bullet – with Edge’s shards of guitar intimating the bombing raids south of the US border – and closing track Mothers of the Disappeared and its direct fingering of Pinochet’s brutality. So as much as the band were seduced by America’s wide open (literal and figurative) spaces, they explored its darkness in equal measure like an aural David Lynch. Other American folk heroes, like Nebraska mode Springsteen and Dylan (any decade), could be heard in the fable-like lyricism of the junkie ballad Running to Stand Still – which, though it was written about Bono’s boyhood home of Ballyum, Dublin, was a picture of urban decay which was sight unspecific.

Once described as a ‘rock and roll bolero’, With Or Without You is the twisted, throbbing heart of the album. A perfect summation of the corrosive effects of sexual jealousy, it was the most musically conventional though thematically complex love song of U2’s career. On the Edge’s specially commissioned Infinite Guitar, the song is an exercise in deceptive simplicity, with its coda repeating the same few noted figure, such was his stubborn refusal to ever play a solo. This song with its character’s inability to leave an abusive relationship, became the band’s first US number one.

So there U2 were, standing straight backed and serious in Anton Corbijn’s desert portraits, staring down the rising tide of crap which surrounded them in 1987: Duran Duran, Rick Astley, Hewy Lewis, Reagan’s America, Gordon Gecko. Though chewed out by Sinatra for “dressing like a bunch of bums”, U2’s low-fi visual aesthetic was their Irish way of rebelling against the US culture which they wanted to be a part of on the one hand, yet so steadfastly refused to be on the other. The self-serious tag would dog them for years to follow until they obliterated it with The Fly and Achtung Baby in the early ‘90s, but it did help to elevate them above the decade’s artifice at the time.

True though it may be that U2 now live in a comfy creative semi-retirement, rehashing their own trademarks to a deafening chorus of nonsensical critical praise, listening to the Joshua Tree 20 years later makes plain its staggering timelessness. Its influence was brought to bear in later decades on everyone from Radiohead to Coldplay to Doves and Interpol. U2 may never reach the dizzying heights they did here and on Achtung Baby ever again, but news that they are working on their next record (slated for release in 2008) with Lanois and Eno once more at the helm is hope enough to hope that perhaps, they still haven’t found what they’re looking for. Boom, boom.

The Joshua Tree 20th Anniversary reissue: three-disc box-set containing The Joshua Tree CD remastered, the bonus demos and b-sides disc, plus the DVD: U2 Live from Paris – filmed at the Hippodrome de Vincennes in Paris, on July 4 1987, on the European leg of The Joshua Tree tour. Includes a 56 page hardback embossed book, featuring previously unseen Anton Corbijn photos, handwritten lyrics by Bono and liner notes by author Bill Flanagan, Bono, Adam Clayton, Brian Eno, Daniel Lanois, Anton Corbijn, Steve Averill, David Batstone, René Castro and an essay by The Edge.

Released ROW, 22/11/2007. Available in Australia, December 10.