When's the last time you read your local newspaper? And, no, I'm not counting The New York Times or The Washington Post. I mean a locally published paper that focuses on local events. Chances are, even if you live in a suburb or a small town, you don't read the paper too often. Your town might not even have one. And that absence, according to a study described recently in Scientific American, might be an overlooked cause of political polarization.

In an earlier account of their research, the authors remind us that in 2016, "more voters cast straight party-line ballots than at any point in the past century." As recently as 1992, more than one out of three states split their ballots, electing a senator of a different party from that which won the state's electoral votes. In 2016, not a single state did so.

So what does the death of local newspapers have to do with this phenomenon? The authors — Matthew P. Hitt, Joshua Darr and Johanna Dunaway — compared federal election results in counties where the local newspaper closed between 2009 and 2012 with results in a list of "statistically indistinguishable" counties where papers hadn't closed. They searched for ticket-splitting — counties where one party's candidate won the presidential ballot and the other party's candidate won the senatorial ballot. They found that the counties that had experienced a closure were 1.9 percent more likely to split their votes.