Here’s the story:
I don’t love that the graph is in alphabetical order (and by state abbreviations, not even the conventional order by state names), nor do I love the x-axis (labeling every five years is overkill and it requires me to squint to figure out which year is which; a simple label every 20 years would be enough) but that’s a topic for another post.
What’s interesting to me is that, yes, there is a strong correlation between liberal or conservative policies and Democratic or Republican voting, this correlation is not 100 percent. Even setting aside the pre-civil-rights South with its tangle of ideologies, we still see patterns such as California being consistently more liberal in its policies than its voting.
Lots to look at here, and lots to look at in the paper that describes Caughey and Warshaw’s research project, the Dynamics of State Policy Liberalism, 1936–2012, which connects statistical estimates of state-level opinion with statistical estimates of state-level policy.