Steve Earle, Shepherd's Bush Empire, London

Steve Earle, reformed junkie and rejuvenated artist, is angry and paranoid. He is angry because his "constitutional right to be bummed out for as long as I fucking want" has been questioned all over the American tabloids, which, since the release of his album Jerusalem, have taken to labelling him "twisted" and "one of those people who hate America". And such is the extent of his paranoia that when he looked the word up and found that it meant "to be fearful of something that is not real" he even got paranoid about the dictionary definition. "I swear to God I'm being followed right now," he tells the crowd at the rammed-to-the-rafters Empire, who are indeed following his every utterance.

What, you may ask, can good ol' Texan country boy Steve Earle – purveyor of bar-room ballads, rocking road anthems and "chick songs" – have possibly done to earn such reprobation? Well, the self-confessed "loneliest man in America" (he really should try and hook up with Michael Moore) dared to imagine himself into the head of John Walker Lindh, the young American who was caught with the Taliban and sentenced to 20 years without due legal process.

That song, "John Walker's Blues", is one of the most astonishing pieces of music you will ever hear (or never hear, if you tune into US radio stations). And he plays it tonight with no introduction, no '"I wrote this song because..." frippery and no after-song feedback session. It speaks for itself: "I'm just an American boy/ Raised on MTV/ And I've seen all those kids in the soda pop ads/ But none of them looked like me/ So I started lookin' around/ For a light out of the dim/ And the first thing I heard that made sense was the word of Mohammed/ Peace be upon him." Oh yeah, and the chorus is a recitation of Sura 47, Verse 19 of the Koran. Sung in Arabic. This ain't rock'n'roll. This is commercial suicide.

But Earle has never been one to play to the gallery. Back in the early 1990s, when Nashville had proclaimed him the saviour of country music, the "hardcore troubadour" was living on the streets, strung out on crack and heroin and listening to Dr Dre. Damned if he even owned a guitar.

His recovery changed his life. If he could kick drugs, he figured, then anyone could do anything. Hell, American kids could find Islam through hip-hop (as John Walker Lindh did, after growing up in a bohemian family with a father who came out as gay while his son was in his teens). Murderers could reform. Earle took to visiting death-row inmates; politicised, urgent, angry, patriotic in a sense his own country will never understand – a reborn redneck who had truly transcended.

Trouble is, Earle's enlightenment has left much of his early material sounding like Bryan Adams. He still plays old favourites such as "Copperhead Road", "Guitar Town" and "Galway Girl", but it's the new political songs – "America V6.0", Conspiracy Theory', "Jerusalem", "John Walker's Blues" and "Ashes to Ashes" (which contains the anti-Springsteen lyric: "Every tower ever built tumbles/ No matter how strong/ No matter how tall") – that provide all of tonight's standstill moments. Just maybe, like Bob Dylan in reverse, in years to come the protest songs and pretty numbers will sit comfortably side by side.

For now, though, Earle is just too fired up by this fresh-fuelled burning in his belly. And forget all about country singers putting tears in your beers. Tonight, Earle puts down one heckler with a scathing, "Man, I fucking hate alcohol." He ends the set with a romp through Nick Lowe's "(What's So Funny 'Bout) Peace Love & Understanding" but the slogan on his T-shirt puts it more succinctly: "Fuck the war!" Too many protest singers, not enough protest songs? All you can say to that is, don't mess with Texas.

Steve Earle and the Dukes: City Hall, Sheffield (01142 789789), tonight; Colston Hall, Bristol (0117 922 3686), Mon