1. Empirical support—U.S. Wisconsin For example, Hedlund and Watts (1986) find that, in the open primaries of Wisconsin from 1968 to 1984, around 30% to 40% of the voters in Republican primaries are Democrat identifiers or independents, and about 40% to 45% of the voters in the Democrat primaries are not Democrat identifiers.

2. Empirical support—U.S. presidential election That an open primary can strongly affect the outcome of the primary election can be most clearly illustrated by recent Republican experience in primaries for U.S. presidential election.

3. McCain The surprising victories for John McCain, who is less preferred by the majority of Republicans, in New Hampshire and Michigan primaries (both open) can be attributed to strong show-up of Independent and Democrat who vote for McCain in the primaries.

4. main purpose of this paper Our main purpose is to study how, and to what extent, strategic voting behavior affects the outcome of the primary. We propose a stylized two-party Hotelling model in which one party holds a primary election before the other. There are two candidates competing for nomination.