In an alternate reality — one in which a mentally unstable gunman did not kill 18 people in Lewiston, Maine, last October — the biggest issue in the race for Sagadahoc County sheriff this fall might have been the budget for the county jail.

Instead, the contest has become a referendum on the actions taken, and not taken, by the sheriff’s office in the run-up to the worst mass shooting in Maine’s history, and a study in the complexities of blame. The incumbent sheriff, Joel Merry, 66, is running for a fifth term, undeterred by the harsh criticism lobbed at his office for failing to seize a stash of weapons from the gunman — who lived in Sagadahoc County — as concerns about him mounted last fall.

His challenger, Sgt. Aaron Skolfield, a 26-year veteran of the same department, was singled out for particular rebuke by the state commission that investigated the shooting. Sergeant Skolfield has turned his campaign into a public crusade to clear his name, and to call out what he sees as unfair scapegoating.

For some voters in the county, the race is an uncomfortable reminder of all that has not changed in the last year — and of all the grief and blame that remains.

Sheriff Merry, who has defended his agency against the criticism, said he was seeking one last term to finish several projects that he hoped would strengthen it. He acknowledged that the election and the mass shooting could not be separated, though he maintained that they should be.

His opponent has also given up on that idea. For Sergeant Skolfield, 52, running for sheriff and defending his actions in the weeks before the shooting have merged into a single quest to reclaim his reputation from disgrace.