Why is IA so much more Dem than neighboring states?

[David Hume]

They are very white and a lot of non-college educated, and no large metros like MN, WI. Yet they vote to the left of neighboring states for decades.

[David Hume]

Actually, it’s less Democratic than exactly half its neighbors.  It voted for Trump twice, while Minnesota, Wisconsin, and Illinois all backed Biden.

I guess it’s safe to assume you’re asking “why is Iowa so much more Democratic than SD/NE/MO?” or “why is Iowa so much more Democratic than other Plains states?”  It’s more Democratic than the sates to the west because it’s much more densely populated, with less ranching.  Also, while Iowa is not as rural as South Dakota, it’s not as suburban as Nebraska (though as a result of trends in the age of Trump, IA and NE are converging somewhat).  As for Missouri, Iowa’s neighbor to the south is for the most part a Bible Belt state (when I was in northern Missouri, the accent sounded Southern-ish to my ears), while Iowa is not a Southern state at all.

As I said, MN WI IL has large metros. Just looking at demographics you would expect them to vote in that way, while IA should be much more republican. (WI also vote more Dem than the state demographics).

[David Hume]

The main difference between Iowa and Missouri is that the former was largely settled by Yankees from New England who brought with them a more liberal political culture than the Southerners who settled the latter.

Isn't IA mainly settled by Germanic immigrants?

[David Hume]

Residual remembrance of the 80's farm crisis which devastated Iowa. Go look at the maps comparing 1980 to 1984 to 1988.

I heard many people saying so. Yet so many years had past and so many things had changed. VT moved from a safe R state to safe D state, WV the opposite. How could the memory of 80's farm crisis last forever?

[David Hume]

There is a simple, structural phenomenon throughout a large segment of the country's interior: the further north and/or east you go, the more liberal people become, and the further south and/or west you go, the more conservative.

A large majority of Iowans live in the eastern half-to-third of the state, and as such, are going to more closely resemble their peers in places like Illinois, Wisconsin and Minnesota - both in rural and urban areas alike.

Half of IA lives in the red; another 20% in the blue. In terms of figuring out why IA seemingly doesn't fit the profile of (largely) states further west, draw some lines from the northwest and southeast of the area in question, and ask yourself if these people are really voting all that much differently than those within the defined boundaries.

If the red area voted Trump 0.6 and Biden 0.4, that's still to the left of non-metro WI and MN you circled, which voted about R+10.

[David Hume]

If the red area voted Trump 0.6 and Biden 0.4, that's still to the left of non-metro WI and MN you circled, which voted about R+10.

The lines were to illustrate the broader point about cardinal directions and the broader effect, but if you take the general orientation of the IA region and extend it along its average east and/or north - while omitting the coastal urban areas (Chicago, Milwaukee, etc), you end up with a very similar balance:

The problem is your way of circling areas are quite arbitrary. I can just extend more into downstate IL like you did into WI, or make the east cutoff westward, to get a very R number I want.

[David Hume]

The main difference between Iowa and Missouri is that the former was largely settled by Yankees from New England who brought with them a more liberal political culture than the Southerners who settled the latter.

Isn't IA mainly settled by Germanic immigrants?

More so along the Mississippi. When my mother was growing up in Davenport, Iowa, in the 1920's and 1930's, the cultural and class differences between the WASPS and Germans was palpable, including considerable neighborhood segregation.

IIRC before WWI a lot of Germans over there still spoke German as mother tongue. They were persecuted after WWI and their German schools got banned.