The assassination of an elected official is rare and shocking anywhere on American ground. Nowhere is it more jarring than in Minnesota, a state known for a singular political culture with high value placed on bipartisanship and a tradition of civic involvement that transcends ideology. “What happened today is simply incomprehensible and unimaginable, certainly in the context of Minnesota,” Norm Coleman, a former senator from Minnesota and former mayor of St. Paul, said in an interview on Saturday. He ticked off a list of Republican and Democratic politicians who had reached across the aisle — Hubert Humphrey, Tim Pawlenty and Amy Klobuchar. “It’s a history of people who tried to find common ground.”

While Gov. Tim Walz of Minnesota, a Democrat, began his political career representing a rural, conservative Congressional district, that career arc seems less imaginable today. The urban-rural divide in Minnesota has become more intense, political strategists said, and the nationalization of party politics has weighed more heavily on voters than local issues.“I don’t see Minnesota as unique anymore,” said Ryan Dawkins, an assistant professor of political science at Carleton College in Northfield, Minn., who studies American politics and polarization. “A lot of the unique character of state politics is not gone by any stretch, but it has become much more muted as polarization has increased.”

Former Gov. Tim Pawlenty of Minnesota, a Republican who was elected in 2002 and re-elected in 2006, pointed to the state’s “nation-leading levels of civic engagement and political civility.” But he acknowledged that it is no longer the Minnesota it used to be. “While we still cling to it,” he said, “even here it’s slipping away.”