During an appearance on Fox & Friends Saturday this morning, Fox News host and putative Republican presidential candidate Mike Huckabee was asked about Donald Trump's soaring poll numbers and Karl Rove's comments on Greta Van Susteren's show last night that Trump is a “joke candidate”:

Setting aside the ethical problems inherent in Fox News hosting one of their own employees to discuss the poll numbers of one of his potential GOP primary opponents, Huckabee's comments about Trump's birtherism are notable. According to Huckabee, who doesn't “think the birther issue is a good issue” and doesn't “agree with it,” people aren't “rallying behind Donald Trump because of the birther issue.”

But the PPP poll that Huckabee and the Fox crew were discussing tells a different story.

According to PPP's write-up, “only 38% of Republican primary voters say they're willing to support a candidate for President next year who firmly rejects the birther theory.” Among that 38%, Trump polls third (with 17%) behind both Romney and Huckabee.

Trump's numbers are considerably better among those who are “not sure” whether they could support someone who outright rejects birtherism, and soar among the 23% of GOP primary voters who say they are only willing to vote for a birther. Among the latter group, Trump's support hits 37%, nearly 24 points higher than the 2^nd place finishers (Huckabee and Palin in a tie).

While Trump's birtherism doesn't explain his entire appeal to GOP primary voters, it certainly seems to help him immensely. And Huckabee's own network - and Sean Hannity in particular - has played a large role in promoting Trump and moving the inane, discredited birther conspiracy from chain emails and WorldNetDaily articles into the Republican mainstream.