Allegheny County Director Corey O'Connor defeated Pittsburgh Mayor Ed Gainey in the city's controversial Democratic primary, which is expected Tuesday after a campaign that was a well-known proxy fight between progressives and the center's left-leaning Democrats.

In the nomination competition, O'Connor led by more than 85% of the votes 54%-46%.

Tuesday's election is one of the first major Democratic primary elections the party has made progress and the center-left faces since the 2024 election. The mayoral campaign follows the election cycle, in which democratic governance in cities occupies a central phase in the Republican campaign news.

Gainey and his allies painted O'Connor as the son of county and former mayor, Donald Trump, and pointed to real estate interests and pointed to campaign donations from Trump supporters and developers. The mayor was first elected in 2021, and he also noted that violent crime, local job growth and the city has improved its credit rating for O'Connor, which portrays Gainey as an ineffective mayor who has failed to achieve in managing the city's financial situation, the police department and the general quality of life circles,

O'Connor launched his campaign late last year, becoming a favorite in the early days and raised more money than Gainey, although polls showed the game's austerity was as Election Day approached. Last month, both sports touted internal polls, showing they have an advantage in hard-to-train local games: Ganey’s campaign survey showed him seven points, while O’Connor showed him four points out of four, although that was closer than other polls than others, and the campaign he touted earlier in the cycle showed challengers improving double digits.

Gainey, the city’s first black mayor, won a controversial primary in 2021, beating incumbent mayor Bill Peduto in one third of the primary and defeated by multiple votes. His victory was part of county-wide advancement, with Rep. Sam (D-Pa.) and Allegheny County executive Sara Innamorato, and other candidates for the left winning major offices in recent years.

Pittsburgh mayor race elevates housing policy to the forefront of local discussions. Gainey attempts to develop inclusive zoning policies across Pittsburgh that require new developments to spend at least 10% of the units on affordable housing. These policies currently apply to only a few communities, and O'Connor does not object to the development of city-wide zoning policies.

Meanwhile, a key debate in the game is how many affordable units the city has or is building since Gainey's tenure as mayor.