LAS VEGAS: Nikki Haley was swamped in Nevada's symbolic Republican presidential primary as GOP voters resoundingly picked the 'none of these candidates' option on the ballot in a repudiation of the former United Nations ambassador, who is the last remaining major rival to frontrunner Donald Trump.

Trump didn't compete in Tuesday's primary, which doesn't award any delegates needed to win the GOP nomination. Instead, the twice-impeached former president is focused on caucuses to be held on Thursday and that will help him move closer to becoming the Republican standard-bearer.