I think, and this isn't something I'd considered much before, that the mouseover's surprising only because, in common colloquial language, we use "there are more X here than there" to mean both "a higher number of X" and "a bigger share of X".
There are numerically more white people in Lagos than in Stornoway, for example, but you wouldn't think that someone who said "there are a lot more white people in Stornoway" was insanely wrong.
Possibly it's also because people don't have an instinctive understanding that states have massively different populations?
I disagree with the OP - I think that's a thing that happened, but it does not by itself explain greater polarisation. It doesn't explain this, for example:
https://www.pewresearch.org/politics/2014/06/12/political-polarization-in-the-american-public/
(and that's almost ten years ago).
Party-line voting has increased a lot since the 70s https://thedecisionlab.com/insights/policy/holding-the-line-social-norms-and-party-line-voting
https://library.cqpress.com/cqalmanac/file.php?path=Party%20Unity%20Tables/2015_Party_Unity.pdf
I'm not saying polarization hasn't happened. I'm just saying that it's dumb to not include the context of Southern Democrats who used to vote across the aisle out of love of hating black people.
Okay, I guess I said it was an illusion. But I didn't mean illusion-illusion. You know, the other kind.
When I was in graduate school the first time, I recall that there were political knowledge questions. One of the questions was "which party is generally the more conservative?" We had to make an allowance for southerners. But really, it was just a bad question.
6: it's allusive and elusive but not completely illusive?
1: It's in implicit contrast with the electoral college mindset that treats the states as uniformly their majority.
And also piggy-backing on states which superficially are lumped together as "BIG" or "Middling" in size. Just adding complexity to the general idea that every state is a purple state, roughly proportional to the amount of city vs rural. (Not entirely of course.)
Are people here fans of David Broockman?
In the 1950s and 1960s say, racism was not necessarily correlated with positions on other issues. You could be a racist and favor a strong safety net, at least for some people. Whether or not you were racist was more or less independent of whether or not you were a dove or hawk on Vietnam.
From Nixon on, open expressions of racism became more and more socially unacceptable. So politicians expressions of certain opinions on other issues became increasing abstract and coded ways of advocating racism.
These are some ways increasing polarization on party lines has happened.
Well, I am glad to be proven wrong about the US SC not getting a clear merits shot at section 3 before the end of the term.
They might be desperately looking for ways to avoid ruling, but the Colo SC has done a pretty good job setting it up so they'll have a tough time ducking.