When you wonder about what “they” are going to decide, are you referring to the political parties in general, or to Orlando Garcia and Xavier Rodriguez, with Jerry Smith dissenting?
No, the two Federal Judges that are delaying the primary dates, and making null and void the redistricting that was accomplished by our legislature, have thrown the people, and State of Texas and state parties election process into utter chaos, and are deciding when the state convention is held.
The Primary Elections are not only for the purpose of polling voters as to which presidential and other candidates they prefer to be listed as party candidates on the General Election ballot, delegates to the County and District Conventions are elected at the Precinct Conventions held right after the polls close. The County and District Conventions are held in part to have an election by these elected delegates to select delegates to represent Counties and Districts at the State Convention, where delegates are named to represent States at the National Convention.
By holding the primary dates and redistricting hostage to the whims of two Federal Judges, the Federal Government has seized control of State Parties with a Convention System as well as the prerogatives of the State of Texas, and therefore; the state party does not decide when the state convention is held.