No Republican presidential candidate stirs more curiosity than Jon Huntsman. "What about Huntsman?" You hear it all the time. Who is Jon Huntsman and where is he coming from? On the morning after he announced his presidential bid in front of the Statue of Liberty this week, we hitched a ride on his campaign plane to South Carolina, seeking answers.

Mr. Huntsman is addressed as "governor" because he was the two-term governor of Utah. Lots of governors run for president. What causes curiosity about Mr. Huntsman is that he has...