Nikki Haley’s bid illustrates the problems of the Republican Party

When a new fighter enters the arena to go up against a legend, the crowd braces for a good show. But if the matchup is too lopsided the brawl is no fun. That was the sense when Nikki Haley, a former governor of South Carolina and Donald Trump’s first UN ambassador, announced her presidential run on Twitter on February 14th, becoming the first Republican formally to challenge her former boss. At a launch event in an open-air shed in Charleston the next day, the crowd roared when she suggested mandatory mental-competency tests for politicians over 75. Ms Haley climbs into the ring as a lightweight. But her candidacy helps illustrate the problems of the Republican Party and the nature of the coming contest.