Democrats and Republicans can at least agree on one thing: They have no idea what’s going to happen in next year’s Arizona Senate race.

The election is shaping up to be an unpredictable three-way contest in one of the nation’s premier battlegrounds featuring an incumbent who left her party, a polarizing conservative who remains a rock star with her base and a Democratic nominee-in-waiting who would represent a jolt to the left for the historically moderate-minded state.

“This is kind of a pick your own adventure,” said John LaBombard, a former aide to incumbent Sen. Kyrsten Sinema. “If a two-way race is impossible to predict, this is exponentially harder to predict.”