Neb. Rev. Stat. §§ 32-702
Any political party may, by the adoption of a rule, require that any individual whose name is placed on such party's partisan primary election ballot be a registered voter affiliated with such party. If the political party adopts or revokes the rule and notifies the Secretary of State by filing the rule or notice of the revocation with the Secretary of State prior to December 1 of the calendar year before a statewide primary election, the rule or revocation is effective for the next and subsequent statewide primary elections. If a rule or notice of revocation is filed with the Secretary of State on or after December 1 of the calendar year before a statewide primary election and on or before the day of the statewide primary election, the rule or revocation is effective for the subsequent statewide primary elections.
Neb. Rev. Stat. §§ 32-702