Turning point or the long game: what’s behind John Roberts’s surprise supreme court voting rights ruling?

John Roberts wrote the Allen v Milligan opinion himself, with the support of the three liberal-leaning justices and the partial backing of conservative Brett Kavanaugh. Composite: The Guardian/Getty Images

The US supreme court ruling delivered on Thursday by John Roberts marks a departure for the chief justice from his 40-year battle to whittle down racial equality protections enshrined in the crowning glory of the civil rights movement.

Roberts wrote the Allen v Milligan opinion himself, forging an unconventional 5-4 majority with the support of the three liberal-leaning justices plus the partial backing of the conservative Brett Kavanaugh. The chief justice’s decision to cling closely to precedent and avoid a sweeping reframing of voting rights law took supreme court observers by surprise.