IT WAS the sort of intervention on behalf of a persecuted opposition politician that Amnesty International carries out hundreds of times a year. In 1998, after Recep Tayyip Erdogan, then the mayor of Istanbul, was jailed for a speech in which he read out a religiously themed poem, the human-rights group termed him a “prisoner of conscience” and wrote to the government demanding his release. Nineteen years later, Mr Erdogan, now Turkey’s president, presides over an increasingly authoritarian regime. And his police force has arrested Amnesty International’s own staff along with other human-rights activists. So it was to Mr Erdogan that the group found itself writing last week to demand the release of detainees. He shows little sign of softening.