From Ballot Access News:
On May 16, former Arizona state legislator Tom O’Halleran said he will run for the State Senate as an independent candidate. See this story. He changed his registration from “Republican” to “independent” on May 14. The petition deadline this year for independent candidates in Arizona is May 28. O’Halleran served in the legislature for eight years as a Republican.
Arizona is one of only a handful of states in which no one has ever been elected to the state legislature except Republican and Democratic nominees. Of course, one reason for that is that Arizona has only been a state since 1912. It is unknown if any minor party or independent candidates were ever elected to the Arizona territorial legislature.
From the article cited, written by Mary Pitzl:
In what might be the best test to date of whether an independent can win a partisan election in Arizona, former Republican state Sen. Tom O’Halleran is attempting to return to the Senate, but this time as an independent.
That means he’ll forego the primary (there is no “independent party” and therefore no need for a primary) and move straight to the Nov. 4 general election for the Legislative District 6 Senate seat, where he’ll face incumbent Sen. Chester Crandell, R-Heber. Democrat Doug Ballard has opened a Senate committee, but indications are he will not run.
Although O’Halleran he doesn’t face a primary, the odds of an independent candidate winning are slim.
The deck is stacked against them: They have to collect hundreds more signatures on nominating petitions than members of established parties, they don’t benefit from the reduced postage rates given the parties, they get less exposure in government-issued publicity pamphlets and their names must always come last on the ballot listing candidates in their race.
For example, O’Halleran needs the signatures of 1,157 independent voters to qualify; Crandell needs only 427 Republican signatures, and Ballard, if he runs, needs 303 Democrats to sign.