If scientists could develop modelling system to predict the yield of a crop in particular area and time by calculating parameters of soil moisture, soil pH, rainfall, temperature range etc there should be some psychological method to gauze the mind of a voter or how to win heart of a voter in a democratic system by permissible means ? Perhaps its too early to suggest this but sooner or later this is going to happen that science will be able to read mind of person opposite to you. Science magazine some time ago put an entire issue on future of science or something like that where wild ideas of writers were given some place . To my mind identifying with the voters in their language, at their level and being one of them in letter and spirit endears a candidate to the voters but to make him vote for the candidate or follow supporters advice in a mature democratic system rests on several parameters. 
Some of the parameters are emotional union with candidate due to several reasons. 
Loyalties of region, religion, casts when stop playing one can imagine the maturity stage of a democracy and its voters. What development means for a common person ? Not a television or a telephone or a computer but something that satiates  his hunger for recognition of his personality as it is and where it is  and any development must root in growth of its roots in a given social system. Politics of "Union" with self and with candidates is a different turf for psychologists to explain  and predict human behavior. Can it happen in near future ?