Arizona's presidential preference election, on March 17, is only open to Democratic voters.
That is different than other primary elections where independent and no-party voters can cast ballots simply by asking for a party's ballot.
"If you want to vote in the presidential preference election and you are an independent or Republican you must register as a Democrat," explained F. Ann Rodriguez, Pima County recorder.
The last day to register as a Democrat in order to participate in the presidential preference election is February 18. You can do that online at Service Arizona or in person at the Pima County recorder's office.
You can change your registration back to your previous party after the election.