While the unconstrained Trump has a comfortable double-digit lead over the soft-spoken Carson, the data points to a possible emerging threat to Trump’s hopes of capturing the party’s nomination for the November 2016 election.

The poll of likely Republican primary voters also shows that Carson is drawing strong support from the rural Midwest, including Iowa, which holds the first Republican nominating contest on Feb. 1. Trump, in contrast, is drawing strong support in the northeast and southeast.

That geographical divide is significant, analysts said, because Carson’s dominance in more socially conservative states like Kansas, Iowa and Nebraska reflects how his story of personal redemption is resonating strongly with evangelical voters. They traditionally play an outsize role not just in the first nominating contest in Iowa on Feb. 1, but in Nevada and South Carolina, which also hold nominating votes in February.