Steve Earle and the Dukes, Shepherd's Bush Empire, London

A defiant blast of politics

In wartime, artistic courage, it seems, is the first thing to crumble. Madonna has withdrawn the military chic of her American Life video for fear of causing offence. The Dixie Chicks have apologised for daring to criticise George Bush, and Kelly Rowland heads a list of musicians who have cancelled British shows since the war in Iraq commenced.

Steve Earle's rebel instincts broker no such compromise, in a 20-year career that has included numerous arrests, a jail term, battles against the death penalty and his addiction to crack cocaine and heroin, the Texan refusenik has held firm. A round, burly, bearded figure in a white "Fuck War" T-shirt, Earle grimaces as he takes the stage and strikes into the snarling Stones riff of "Amerika v 6.0 (The Best We Can Do)".

The band's drum riser and speaker stacks sport Stars and Stripes emblazoned with the legend "No Iraq War" and the song bemoans the wholesale corporate takeover of the USA. Then, as it reaches the close, Earle inserts an unscripted coda of an unhinged demagogue, screaming: "Let's blow up Iraq, I mean North Korea, I mean Iraq, I mean Texas..."

Since he emerged with the breakthrough Guitar Town album in 1986, Earle has covered the stylistic waterfront between rock, country, bluegrass and folk protest. But, though often compared to Bruce Springsteen, Earle is a more truculent and uncompromising performer, whose wintry discontent is never far away.

His speciality is defiant songs written and sung from the outsider's perspective: the marijuana-growing hill farmer in the heavy metal bluegrass stomper "Copperhead Road", the small town dreamer of "Someday", death row inmates on the dramatically striking "Billy Austin and The Truth".

The selections from the current, avowedly political Jerusalem are delivered with minimal fuss or introduction. "John Walker's Blues" – written from the viewpoint of the Orange County youth arrested fighting with the Taliban in Afghanistan – may be the first country rock song with a chorus sung in Arabic, but it's perfectly in keeping with other outsider anthems in the Earle canon.

Notably, he relies on a selection of covers to deliver much-needed optimism at the close. A rough-hewn version of The Youngbloods Sixties love and peace peaen "Get Together" provides a reminder that, while darkness, anger and artistic principles are Earle's strong points, he finds joy and emotional uplift harder to locate.