“Wisconsin is proof that politicos have short memories. In 2004, Democratic presidential candidate John Kerry carried Wisconsin by just 0.4 percentage points — making it the closest state in the country. Four years earlier, it had been even closer — Democrat Al Gore won the Badger State by just 5,708 votes, or 0.2 points.
But Democrat Barack Obama really connected with Wisconsin voters, winning the state by 14 points in 2008 and 7 points in 2012. Going into 2016, that contributed to a sense that Wisconsin was a safe bet for Hillary Clinton — part of the mythical “blue wall.” It had, after all, voted Democratic in seven consecutive presidential elections by that point.”
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“Conventional wisdom says that Clinton lost Wisconsin because she infamously did not visit the state at all during the final seven months of the 2016 campaign. But that’s probably not true; Clinton devoted a lot of effort to winning Pennsylvania and still lost there, for instance. Instead, Wisconsin probably got redder in 2016 for the same reason that Pennsylvania and other Midwestern states did: demographics. The one-time home of progressive stalwarts like Robert “Fighting Bob” La Follette and Victor Berger could not escape the modern reality that white people without a bachelor’s degree — who make up 59 percent of Wisconsin’s population age 25 and older — have become more and more Republican, especially in the Trump era.”
https://fivethirtyeight.com/features/wisconsin-was-never-a-safe-blue-state/