What characterizes an open primary?

An open primary is characterized by allowing any voter to participate in the primary election process, regardless of their party affiliation. This means that individuals can choose which party's primary to vote in without having to be registered as a member of that party. This system encourages participation from a wider range of voters, including those who may not be affiliated with a political party or who identify with several parties.

In contrast, other types of primaries serve to restrict participation. For instance, a primary limited to registered party members excludes independent voters or those registered with different parties. Similarly, requiring voter identification could apply to various election types but does not specifically define the nature of a primary. A primary exclusively for candidates of the same party also does not reflect the open nature of the primary system being referenced.