But perhaps most illustrative of the fact immigration is a peripheral issue in Trump’s rise is a Quinnipiac poll released Thursday that asked voters to describe Jeb Bush and Donald Trump with the first word that came to mind. Though 9 of the poll’s 1,563 respondents mentioned immigration as a word that came to mind when they heard the name Jeb Bush — not itself a big number — for Trump, “immigration” did not even meet the 5-mention threshold to be included in the list of words that respondents thought to mention. It’s possible not a single person of the 1,563 polled brought it up.

So if not immigration, what is driving Trump’s success? There are probably several factors, but among the most important seem to be Trump’s brash attitude, his business success and his position as an outsider.

Last week in Virginia, pollster Frank Luntz put together a focus group of current and former Trump supporters.

“They love the Trump swagger and attitude,” Fred Barnes, one of the reporters in attendance, wrote in The Weekly Standard. “Luntz asked what they liked the most, the Trump persona or his policies.  Persona got 23 votes, policies six. Shown a video of Trump’s insisting that he would be the greatest president ever, they were untroubled by his boastfulness. Several said Trump was merely displaying his confidence. ‘I like his confidence,’ one woman said, ‘it makes me feel confident.’”