Mass. Gen. Laws ch. 53 § 2
Except in the case of municipal nominations where a city charter or a law applying to a particular town otherwise provides and in the case of nominations to regional district school committees elected district-wide, candidates of political parties for all elective offices, except presidential elector, shall be nominated and members of political committees, except as provided in sections one and four of chapter fifty-two, shall be elected in primaries or caucuses; provided, however, that the state secretary shall not conduct presidential and state primaries in any biennial state election year for a political party which has enrolled fewer than five percent of the total number of registered voters in the commonwealth as of the most recent count submitted to the state secretary under section thirty-eight A, and whose state committee files with the state secretary a writing so requesting, not later than August first preceding a year in which a presidential primary is to occur and otherwise not later than February first of the year of the biennial state election. All nominations and elections in primaries and caucuses shall be by direct plurality vote. No candidates shall be nominated, and no member of a political committee or convention delegate elected, in any other manner than is provided in this chapter or chapter fifty-two.
Mass. Gen. Laws ch. 53, § 2