This is important:
Trump’s recent comments about President Obama waging a war on Christianity don’t hurt him much with the GOP base. 69% agree with the sentiment that the President has waged a war on Christianity, with only 17% disagreeing. Trump’s probably not hurting himself too much with his negativity toward Muslims either―only 49% of Republicans think the religion of Islam should even be legal in the United States with 30% saying it shouldn’t be and 21% not sure. Among Trump voters there is almost even division with 38% thinking Islam should be allowed and 36% that it should not.
(Jensen; boldface accent added)
The 2016 Republican presidential nomination contest is already strange enough. The numbers from the latest Public Poilcy Polling survey of Iowa paint a striking picture.
Ben Carson is by far and away the most well liked of the Republican candidates in Iowa. 77% view him favorably to only 11% with an unfavorable opinion, with the next most popular GOP hopeful having only a 62% favorability. He has just continued to get more popular after posting a 69/10 favorability last month, and his support for the nomination is up from 12% to 17%.
Or, as Steve Benen noted:
After Ben Carson said Muslims should be disqualified for the presidency because of their faith, his campaign manager boasted, “While the left wing is huffing and puffing over it, Republican primary voters are with us at least 80-20. People in Iowa particularly, are like, ‘Yeah! We’re not going to vote for a Muslim either.'”
Given the PPP findings, it seems Team Carson, as offensive as its posture is, knows its audience.
The same poll, by the way, found that 69% of Iowa Republicans―over two-thirds―believe President Obama is “waging a war on Christianity.”
It often seems difficult to imagine this manner of human animus driving such powerful political influence, but on those occasions that we hear about poll respondents reaching record lows for identifying as Republicans, as we sometimes do, perhaps it might be useful to seriously consider who those people are. 
Perhaps, despite the revealing 2012 postmortem, this is all the GOP had to rebuild with.
More significantly than Donald Trump being the height of the Republican brand is the suggestion that Dr. Ben Carson might be the height of the conservative Christian brand. This possibility really is a vital key to understanding what happens in the coming weeks and months of the Republican contest.
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Image note: Top ― Detail of Saturday Morning Breakfast Cereal by Zach Weiner, 12 June 2015
Benen, Steve. “Poll: Nearly a third of Iowa GOP wants to criminalize Islam”. msnbc. 23 September 2015.
Jensen, Tom. “Trump still leads Iowa; Clinton in good shape”. Public Policy Polling. 22 September 2015.
This Is 