(1) Each political party which is organized in Nebraska shall file a copy of the party's plan for selecting delegates and alternate delegates to the party's national convention with the Secretary of State on or before December 1 of the calendar year prior to each presidential election year and shall include a summary of the contents of the plan. The delegate selection plan shall:

(a) Require that at least eighty percent of the delegates and alternate delegates are committed to a candidate for President of the United States based on the results of a caucus or the primary election;

(b) Specify whether the delegates and alternate delegates are committed to a candidate for President of the United States based on the results of (i) a caucus system which is open to all Nebraska residents who are affiliated with the party for purposes of registering to vote in Nebraska, (ii) election at the statewide primary election, or (iii) a combination of the methods listed in subdivisions (i) and (ii) of this subdivision;

(c) Specify how the delegates and alternate delegates are committed for purposes of voting for candidates for President of the United States based on the results of the caucus or primary election; and

(d) Provide that the delegates and alternate delegates are either awarded to the winner of the caucus or primary election or awarded proportionally, based on the number of votes received by each presidential candidate at the caucus or primary election, to each presidential candidate who received at least fifteen percent of the votes for the nomination.

(2) When candidates for the office of President of the United States are to be nominated, every registered voter of a political party shall have the opportunity to vote his or her preference on his or her party nominating ballot for his or her choice for one person to be the candidate of his or her political party for President of the United States by writing the name of the person of his or her choice for President in the blank space to be left upon the ballot for such purpose and making a cross or mark in the square or oval opposite the written name or by making a cross or mark in the square or oval opposite the printed name of the person of his or her choice.