The arrest of a Japanese journalist in Iran has puzzled observers and prompted speculation that it is linked to the US threat to attack the country over its nuclear programme. On Tuesday, Radio Free Europe reported the arrest of Shinnosuke Kawashima, the Tehran bureau chief for Japan’s national broadcaster NHK. The US government-funded news outlet reported that Kawashima was first detained on January 20 and later taken to the notorious Evin Prison, which has been used to hold political prisoners...