“I find when you have firsthand knowledge of things as opposed to secondhand, it makes a much stronger impression,” Mr. Carson said in an interview before his departure, planned for late Thanksgiving Day on a charter aircraft…

Mr. Carson acknowledged that his slippage in the Iowa polls, where he dropped 10 percentage points in a month in surveys by Quinnipiac University, was because voters did not see him as the right person for the Oval Office at a time of fear of terrorism.

“I would agree with that assessment,” he said. “That’s why it’s a good thing it’s a marathon, not a sprint. As time goes on they will begin to listen more carefully to what I’m saying.”

His advisers framed the Jordan trip as an effort to improve his knowledge of the refugee crisis, no less than to demonstrate his credibility on foreign policy.