Polls have opened in a key by-election in regional Australia, viewed as an electoral test of support for the right-wing populist One Nation party, which could win its first federal lower house race. The contest in Farrer, a vast regional electorate in New South Wales, was triggered by the resignation of Sussan Ley, who quit when she was ousted as the opposition conservative Liberal Party leader after nine months. While the Liberals are running a candidate to replace Ley, opinion polls suggest