firehouse primary
n.— «The nature of the caucus, or as it is sometimes call the “firehouse primary” because voting takes place in an open room rather than in a closed polling booth, requires more personal, diligent grass-roots organization and wooing of party activists than do most primaries.» —“McGovern Takes Blame for ’72” by Jules Witcover Washington Post Oct. 26, 1975. (source: Double-Tongued Dictionary)