Tucson voters will choose among three Democrats and an independent for the city’s next mayor — after no Republican turned in enough signatures by Wednesday’s deadline to qualify for the ballot.

Incumbent Democrat Jonathan Rothschild is stepping down at the end of the year after serving eight years as mayor.

Three-term City Councilwoman Regina Romero, former state Sen. Steve Farley and downtown developer Randi Dorman each turned in roughly double the number of required signatures — about 3,900. That threshold makes any court challenges to the three Democrats’ petitions difficult.

The trio will face off in a vote-by-mail primary on Aug. 27 to determine whose name will appear on the Nov. 5 general election ballot.

Ed Ackerley, who co-owns Ackerley Advertising, is running for mayor as an independent. Absent a challenge to his petitions, he will be on the November ballot.

The sole Republican candidate for mayor, Sam Nagy, failed to turn in enough signatures.

In the race for Tucson City Council seats, four Democrats are vying to take the west-side Ward 1 seat Romero is vacating.