One of the unsettled questions in direct primary legislation is the test of party affiliation. Upon what terms should the voter be permitted to participate in the selection of partisan candidates? Should he be required to prove past action with the party whose primary he would attend, or should a mere declaration of present intention to give it his future support suffice?

The former requirement may take the form of an oath that the voter has generally supported the candidates of the party in the past, or at least at the most recent election. Such a test of party affiliation has the apparent advantage that it protects the party primary from invasion by members of other parties for improper purposes, and thus preserves the purity of the partisan nominating system. This advantage, however, is more apparent than real. There is no effective way of discovering a case of perjury without at the same time violating the secrecy of the general election ballot. An oath which can be neither gainsaid nor corroborated excludes only the conscientious voters, who do not need it, and admits the unscrupulous members of all parties.

A less objectionable test of party affiliation may take the form of a declaration that the voter has not participated in the primary election of any other party within a prescribed interval. This declaration may be enforced by a system of party registration, which will impose material obstacles to capricious or dishonest changes of party affiliation.