Calling her a "birdbrain" and warning that those contributing to her campaign will be "permanently barred from the MAGA camp," former US President Donald Trump is attempting to bully Nikki Haley into quitting Republican nomination race amid growing disquiet in the country about his politics of vengeance.Trump went after Haley on Thursday after securing a comfortable win in the New Hampshire primary, denigrating her in sexist terms after she pledged to continue fighting for the nomination despite losing to him in the first two states that had inner-party elections.