Former Mesa Mayor John Giles, the longtime Republican whom Democratic Gov. Katie Hobbs reportedly plans to name as her running mate, left the Republican Party in May, Axios reported on Wednesday. If Hobbs announces Giles, he’ll join the incumbent as part of Arizona’s first gubernatorial ticket with a lieutenant governor. But Wednesday’s revelation changes the political calculus.

Hobbs’ reported choice would symbolize a bipartisan coalition against Republican nominee Andy Biggs. But Giles formally left the Republican Party after several election cycles of supporting prominent Democrats. His history gives Hobbs a recognizable symbol of Republican rejection of the Trump-era GOP. It’s less clear how many voters who still identify with that party he can bring with him.

Axios obtained the voter record that shows Giles is no longer a registered Republican. But that doesn’t mean he never was one. The records described by Axios show that he registered as a Republican in 1986, regularly voted in Republican primaries and participated in every general election from at least 1998 until this year. He briefly registered as an independent in 1998 before returning to the Republican Party. As a registered Republican, he served as Mesa mayor from 2014 through 2025 and built a reputation as a business-oriented, pragmatic municipal official. His break became visible nationally only after the party moved in a direction he said he could no longer support.

By the time the running-mate report surfaced this week, Giles’ formal registration had caught up with a political migration already years in progress. He’s said he voted for Joe Biden in 2020, primarily to oppose Donald Trump. In 2022, he joined Republicans for Mark Kelly and endorsed Hobbs over Kari Lake; the Maricopa County Republican Party censured him. In 2024, he publicly endorsed Kamala Harris, appeared as a Republican surrogate and spoke at the Democratic National Convention, saying he felt more at home there than in the contemporary GOP.

So it should not have come as a surprise when Giles changed his registration to no party preference in May. The Hobbs campaign announced his reelection endorsement on June 26 and called him a ‘former Republican mayor.’ After leaving the GOP, he selected a Democratic primary ballot—an option available to Arizona voters registered with no party preference and not equivalent to registering as a Democrat.

Biggs completed his ticket by naming conservative state Sen. Sine Kerr as his running mate. Days later, reports of the Giles selection created a contrasting picture: Hobbs was assembling a moderate coalition against a Trump-endorsed Republican. The registration news complicates that framing. Giles’s selection still demonstrates that some traditional, McCain-style Republicans consider Hobbs the safer governing choice. But it raises the question of whether he can move current Republican voters—or whether he merely represents voters who’ve already left the party behind.

Giles didn’t have to leave the Republican Party to join Hobbs’ ticket. Hobbs, it bears repeating, hasn’t formally announced him. Can a politician who endorsed Democrats in 2020, 2022, 2024 and 2026 still speak to movable Republicans inside the current party?  Or is he primarily a symbol for independents and former Republicans already open to Hobbs?

Neither Hobbs nor Giles has publicly explained the May change, whether it preceded or followed running-mate discussions, or what Giles believes his political identity is now. Until Hobbs and Giles explain the change, the ticket’s bipartisan message rests on a distinction Arizona voters will have to judge: whether Giles is a Republican crossing the aisle, or a former Republican whose registration finally caught up with his endorsements.