Now it's up to the voters

After months of rallying and tens of millions in campaign ads, voters in Iowa will finally have their say. And in the last few hours, candidates are scrambling to reach as many of those voters as possible. Some of the key questions we hope to answer: How strong is Donald Trump's grip on the Republican party? Can any of his rivals beat expectations and change the nature of the race? And how will the weather - subzero temperatures, dangerous travel conditions - complicate things? CNN is covering the caucuses from all angles. Learn more about your ad choices. Visit podcastchoices.com/adchoices