Nikki Haley and Ron DeSantis were set Wednesday night to clash one-on-one in a final Republican debate before the Iowa caucuses in which they hope 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 will get their first chance to spar without the distraction of lower-performing candidates like former New Jersey Gov. Chris Christie, who dropped out hours before the clash. But regardless of what happens at the debate, Trump remains the overwhelming favorite in Iowa and nationwide, despite his m…