Although he isn't generating the headlines enjoyed by Trump, Carson has quietly built a dedicated network of supporters in Iowa. During the past month, he also aired more ads than any other presidential candidate in Iowa. Carson has the highest favorability rating among Republican candidates, with 79 percent of likely GOP caucus-goers seeing him positively.
Those glowing views of Carson, who has a compelling life story and is seeking to become the nation's second black president, could make it hard for Trump or other rivals to attack him as the campaign heats up this fall. Christian conservatives, who represent nearly 40 percent of likely caucus participants in the poll, may be starting to coalesce around the former director of pediatric neurosurgery at Johns Hopkins.