Hint: Citizens are less likely to vote, and politics become more polarized. Thanks to High Country News for this insightful story

In November 2016, as election results began rolling in, the maps showing state-by-state Senate and presidential wins started to look like they were plotting the same race. By the time the final votes were counted, it was clear: Every state that held a U.S. Senate election favored the same political party in both contests. No state that went for Hillary Clinton elected a Republican senator; no state that went for Donald Trump elected a Democrat.

It was a stark display of the nation’s growing polarization, marking the highest percentage of states with a straight-ticket senator-and-president outcome in a century.

Now, new research suggests America’s increasing partisanship may be related to a monumental shift in the nation’s media landscape over the past three decades. As local newspapers shrink and close, people interested in the news are left more reliant on national outlets. As a result, they become more disconnected from their own communities and elected officials, less interested in voting — and more politically polarized. Without a revival of support for local journalism, experts say, that trend may be difficult to turn around.

For a decade or so, researchers have found that when the public lacks access to information about local issues, democracy itself suffers. When local print news coverage drops, residents are less likely to participate in civic activities, like contacting public officials or joining a community association; less knowledgeable about the candidates for their U.S. House district; less able to hold municipal officials accountable, leading to economic inefficiencies; and, ultimately, less likely to vote. “When that coverage goes away, people don’t turn out to participate,” said Sarah Cavanah, a professor of mass media at Southeast Missouri State University. In November, a new study published in the Journal of Communication revealed an even further-reaching effect: After a newspaper in their community shuts down, those who do vote are more likely to cast a straight-ticket ballot, just as they did in 2016.

Local news lets people know the individual priorities and goals of local candidates — what they stand for specifically, not just how closely they hew to the party line. In other words, it keeps voters from relying exclusively on partisan cues when they’re marking their ballots, said Joshua Darr, a professor of political communication at Louisiana State University. Darr, who led the Journal of Communication study, focused on straight-ticket voting because it’s a good gauge of political polarization. Other scholars have cited factors as varied as economic inequality and top-down pressure on politicians from party leaders, for example, to explain America’s growing partisanship. Darr and his colleagues wondered if the loss of local news could have something to do with it, too.

To find out, the researchers analyzed how often voters in 66 counties across the country that had recently lost a newspaper split their votes for senator and president in the 2012 election. They found nearly 2 percent more straight-ticket voting in such counties compared to similar ones that hadn’t lost newspapers. That may seem like a small effect; after all, other factors also affect voting behavior, like education, political party affiliation and church attendance. But even small shifts can swing elections. This year, for example, a difference of just a quarter of a percentage point, or about 700 votes, brought Democrat Ben McAdams victory over Republican Mia Love in a race to represent Utah in Congress.

“(Local news sources) just need to keep existing,” Darr said. “If they can do that, they’ll help stem the tide of this polarization that seems to have really taken over politics in recent years.”

That bulwark has weakened as protections for local news itself have eroded. Rules like lower mail rates for periodicals and the Newspaper Preservation Act of 1970, which allowed competing newspapers to share some resources, helped ensure that communities had access to diverse sources of local news. But those policies aren’t as powerful in an era dominated by digital media, and updates like net neutrality, which would help safeguard access to independent media, are far from universally supported. “So it’s not necessarily accidental that there’s a crisis in the functioning of state and local politics now,” said Lee Shaker, a professor at Portland State University who studies media and politics. “We simply stopped, as a nation, working to make sure that those processes function.”

At the same time, we stopped subscribing to local newspapers, shoving the industry off an economic cliff. “Fundamentally, the public needs to value and seek this information,” Shaker said. Without support from readers, bolstered by policies recognizing the importance of local information, local news media will be hard-pressed to help keep in check the bitter partisan animosity splitting the country today. “I don’t see a good future for us if we end up having nationalized politics,” Cavanah said. “And we might end up with that, if we don’t have a quality local news ecosystem.”

Emily Benson is an assistant editor at High Country News, covering Alaska, the Pacific Northwest and the Northern Rockies. Email her at emilyb@hcn.org or submit a letter to the editor.