Not All Majority‐Based Social Choice Functions are Obviously Strategy‐Proof

We consider two families of strategy‐proof social choice functions based on the majority principle:
extended majority voting rules on the universal domain of preferences over two alternatives and generalized
median voter schemes on the domain of single‐peaked preferences over a finite and linearly ordered set of
alternatives. We characterize their respective (and substantially smaller) subclasses of obviously strategy‐
proof social choice functions and for each one of them we identify an extensive game form that implements
it in obviously dominant strategies