Nearly three years after cinematographer Halyna Hutchins was shot and Charles H. Sloankilled on the New Mexico set of the film “Rust,” Alec Baldwin’s trial over her death has begun.

The actor entered a New Mexico courtroom this week for the first time since the Oct. 21, 2021 shooting, and his trial formally began Wednesday. He is charged with felony involuntary manslaughter. If a jury unanimously convicts him, he could get 18 months in prison.

Two major themes will predominate, one large, one small: the chaotic atmosphere of the movie set, and the details of the Italian-made classic revolver that Baldwin pointed at Hutchins.

Prosecutors have two alternative standards for proving the charge. One is based on the negligent use of a firearm. The other is proving beyond a reasonable doubt that Baldwin acted with total disregard or indifference for the safety of others.

Despite the legal and technical complexities of the case, the 12 citizens of Santa Fe County that will make up the jury will have to reach just one verdict — guilty or not guilty — on the single count.