Nikki Haley and Ron DeSantis Wednesday night clashed one-on-one in a final Republican debate before the Iowa caucuses in which they hoped to derail former President Donald Trump’s seemingly unshakable grip on the nomination. With each of them hoping to elbow out the other, Haley and DeSantis got their first chance to spar without the distraction of lower-performing candidates like verbal bomb thrower Vivek Ramaswamy and former New Jersey Gov. Chris Christie, who dropped out hours before the clash. It gave voters a more unvarnished look at the two main rivals to Trump. They wasted little time t…