This chapter examines and models the effects of partially binding campaign platforms in a political competition. Here, a candidate who implements a policy that differs from the platform incurs a cost of betrayal, which increases with the size of such betrayal. It also analyzes endogenous decisions by citizens to run for elections. The model is able to show two implications that previous frameworks have had difficulty with. First, candidates with different characteristics have different probabilities of winning an election. Second, even knowing that he/she will lose an election, a candidate will still run, hoping to make an opponent’s policy approach his/her own.