History suggests that the eventual nominee will emerge from 2015 in one of the top two or three positions, as measured by endorsements, fund-raising and polling.
http://www.nytimes.com/interactive/2...08.mobile.html
Bush and trump are 1 and 2
The polls get most of the attention, but they?re not the most important part of the early stages of a presidential campaign. The better guide to who?s really winning is known as the ?invisible primary,? in which candidates compete for support from their fellow politicians, from party leaders and from donors.
The candidate who wins the invisible primary usually wins the nomination. Even when he doesn?t, the eventual nominee tends to be a candidate who was a close runner-up.