Hawaii constitution
Article II
Section 4

The legislature shall provide for the registration of voters and for absentee voting and shall prescribe the method of voting at all elections. Secrecy of voting shall be preserved; provided that no person shall be required to declare a party preference or nonpartisanship as a condition of voting in any primary or special primary election. Secrecy of voting and choice of political party affiliation or nonpartisanship shall be preserved.