Del. Code tit. 15, § 3189

The name of each presidential candidate in the presidential primary shall appear on the primary election ballot in accordance with § 3124(b) of this title. In any presidential primary election, each voter shall be permitted to vote 1 vote for 1 presidential candidate of the party of the voter’s registration as shown by the voter’s original permanent registration record. The last day that a voter may change his or her political party affiliation before the presidential primary election shall be the sixtieth day before the day of the aforesaid election.