Democratic Pittsburgh Mayor Ed Gainey lost Tuesday’s mayoral primary election to the comparatively moderate Democratic Allegheny County Controller Corey O’Connor,

Corey O’Connor first toyed with the idea of trying to unseat Pittsburgh Mayor Ed Gainey about a year ago. In his role as Allegheny County controller, he often talked to residents throughout the city — and what he heard was frustration.

The Democratic primary for mayor of Pittsburgh on Tuesday has become something of a proxy for the national struggle over the party’s future direction.

On Monday, as voters dropped off their mail-in ballots, many were focused on a single race: the match-up between incumbent Pittsburgh Mayor Ed Gainey and challenger County Controller Corey O’Connor.