The country star is not always remembered for his politics, but his about-face to withdraw support for Nixon and the Vietnam war may be his finest moment

“I speak my mind in a lot of these songs,” Johnny Cash wrote in the liner notes to the album Man in Black, released 50 years ago today. He might be better known now for the outlaw songs of his youth or the reckonings with death in his final recordings, but Cash used his 1971 album to set out his less-discussed political vision: long on feeling and empathy, and short on ideology and partisanship. The United States seemed hopelessly polarised, and Cash confronted that division head-on, demanding more of his fellow citizens and Christians amid the apparently endless war in Vietnam.