When Mike Huckabee became lieutenant governor of Arkansas in 1993, he complained of being burdened by college tuition bills for his son, the expenses of two residences — one in Texarkana and the other in Little Rock — and the cost of commuting between the two. With an annual salary of $25,452, he said he was falling short in covering the bills. “It was costing me money to be lieutenant governor,” Mr. Huckabee recalled in a 1997 newspaper interview. To bridge the gap between his income and his expenses, Mr. Huckabee and a few close political advisers came up with...