The child’s birthday party was going strong in Douglasville, Ga., during the summer of 2015 when the convoy of men and women waving Confederate battle flags drove up. The partygoers, most of them black, were grilling and celebrating. Then the people in the pickups pulled out a shotgun, prosecutors said later at trial.

“Members of the group pulled out a shotgun and pointed it at the victims,” District Attorney Brian Fortner said in a statement. “They used racial slurs and threatened to kill some of the partygoers. They even threatened to kill children at the party.”

Mr. Fortner added, “This is behavior that even supporters of the Confederate battle flag can agree is criminal and shouldn’t be allowed.”

This week, Judge William McClain of Douglas County Superior Court sentenced one of the men and a woman among the group to lengthy prison sentences for their part in the confrontation. He said, “Their actions were motivated by racial hatred,” according to The Atlanta Journal-Constitution.