Things have been going so well for Shinzo Abe and his ruling Japanese coalition – historically high approval ratings, a booming stock market, full control of parliament for the first time in six years – that it would take an almost perverse imagination to devise a way to screw it up. Enter Taro Aso and the Nazis.

In a bizarre and offensive gaffe this week, Mr Abe’s deputy premier and finance minister appeared to praise the National Socialists’ furtive undermining of Germany’s interwar constitution. Their methods, he suggested to supporters, could serve as a model for Japanese conservatives as they seek to revise their own country’s basic law.

“We should proceed quietly,” transcripts from Monday show him saying. “One day, people realised the Weimar constitution had changed into the Nazi constitution. No one had noticed. Why don’t we learn from that approach?”