Chris Christie
Prediction markets: 10 percent
Next up is the first major change in the list since last week. On June 14, the third most likely choice was Joni Ernst, who at the time was at 7 percent. She has now dropped down to number four and is currently at 5 percent on PredictWise. Overtaking her is New Jersey Governor Chris Christie, who has risen four points from 6 percent last week to 10 percent this week. Christie would bring governing experience to the table, although he's no Washington insider, and it doesn't hurt that Christie has also gained a reputation for being a "straight shooter" with a similar temperament as Trump. He was also the first major establishment Republican to endorse Trump, and he has been rather loyal to him ever since, repeatedly defending the New York businessman when few other Republicans would. On the other hand, it's unclear how Christie would really help Trump, considering he is an unpopular governor from a blue state. (Getty)