The Republican candidate in this election is polling poorly in Utah - to the point where the polls have suggested that he and Hillary Clinton are running even in the state. This is thanks to his unpopularity among Mormon voters, who object to his rhetoric and overall obnoxious behavior (as well as his criticism of Mitt Romney, who is popular in the state), and because both Evan McMullin and, to a lesser extent, Gary Johnson are drawing support away from him:
McMullin, a Utah native and former CIA operations officer, launched an independent campaign after being dissatisfied with the current Republican nominee. He is running as a conservative, hence why he is drawing support from Republican voters, to allow people with right-leaning views to have a better choice that the current nominee, whom he strongly criticizes.
While McMullin's chances of winning outside Utah are non-existent, statistician Nate Silver suggested a way that he could win the election if a victory from him in Utah caused both main party candidates to fail to reach 270 electoral votes:
Evidently, I do not support McMullin's policies. However, I support his willingness to take a stand and put himself up as a candidate rather than whine about yet still support the Republican nominee, as so many others have done. If Clinton wins Utah, she'd be the first Democrat in over 50 years to do so. If McMullin wins, he'll be the first third-party candidate to wins electoral votes since 1968. Either of them emerging victorious in Utah would send a clear message that the hate-filled rhetoric coming from the Republicans is not acceptable.