Kansas is no swing state. The landlocked expanse of farms and Protestant churches hasn’t supported a Democratic presidential candidate since 1964, and hasn’t sent a Democrat to the Senate since the 1930s. It inspired a 2004 book, “What’s the Matter With Kansas: How Conservatives Won the Heart of America,” that foreshadowed the rise of anti-elite conservative populism that would carry Donald Trump to the presidency.
And yet, in a sense, Kansas is a swing state this year. The stat...