After the election, Mr. Calhoun held a small gun rights rally in town, and the violent posts continued, with talk of civil war, mounting heads on pikes and showing the Democratic congresswoman Ilhan Omar “what the bottom of the river looks like.” In December, a reporter for The Globe and Mail, a Canadian newspaper, found Mr. Calhoun buying a Confederate flag outside a Trump rally. “This is about independence and freedom,” Mr. Calhoun told the reporter, describing Trumpism and Southern secession as similarly justified fights against tyranny.