Gautam Mukunda wrote a book about the two types of leaders: filtered (those that rise through the ranks, and build a following of influential people supporting them), and unfiltered (those that bypass the standard path to the top, and go straight to the highest level). Mukunda has developed a
"Leadership Filtration Process," where processes for leader selection are either tightly controlled, or more open and loose. Churchill, Teddy Roosevelt, Lincoln, and more, were unfiltered, meaning they rose to the top, circumventing the tightly controlled process of grooming. Filtered leaders are less likely to surprise, and more inclined to follow the rules. Unfiltered leaders, however, are the fun ones. They can be explosive, and are rarely forgotten. However, they are prone to either great success or great failure, but rarely inbetween. Some of the best presidents in history were unfiltered. But some of the worst were unfiltered too. Voting for an unfiltered leader is a high-stakes gamble, with the future of the organization or the nation on the line. 

For the record, Obama and Romney are both unfiltered leaders. Good luck.