Obama had a certain type of style that played very well in the Midwest. See his 2004 DNC Keynote speech for an example.
This was what I was gonna say. Mahoning County, OH is one of the most striking places to me. Obama actually increased his margin in 2012 over 2008. After that though, Biden actually did worse than Hillary. Hillary actually held on to the county by a slim margin, but it somehow flipped to Trump in 2020.
One thing worth noting is that Obama doing significantly better nationwide, he really didn't improve over Kerry or Gore in Mahoning County. When you look at the partisan lean of the County relative to the nation, it's had a pretty clear rightwards trajectory for a quite a while. I think a lot of this can be attributed to ancestral D support already going away pre-Obama and Youngstown itself shrinking.
The bounce left in 2012 is interesting and happened with quite a few industrial working class rural/small-town Ohio Counties. I think it could be attributed to specific campaigning in Ohio and the auto-bailout.
Actually, one thing that's fairly remarkable was Kerry's performance in the state. It was the first time the state voted left-of-centre since 1972. Apart from landslides on either side (adding 1964 and 1920 to the list), you have to go back to 1916 to find the last time it voted more Democratic than the nation as a whole. For most years, Ohio has been stubbornly just to the right of centre.
I think Obama's result in Ohio in 2008 was disappointing at a relative level. The swing map shows a strong result for him in NWOH (interestingly adjacent to the huge swings in Michigan and Indiana). The trend map showed a serious weakness, particularly adjacent to PA and WV. Most of the of attention in that election was focused on the rightward swing in Western PA. However, Obama's 2012 performance in Ohio was quite exceptional considering. The surrounding areas all trending against him. He put up the best performance in Mahoning County since LBJ. He was also only the fourth Democrat to break 60% in Trumbull County, not quite reaching Kerry's record as best performance since LBJ.
(To note one other thing not really related to the above, but Obama lost Pike County in Southern Ohio by just a single vote. Eight years later, it posted the worst swing for Biden in the state, leaving him with just 25% of the countywide vote.)
Yeah I've thought about this a lot too, especially since Obama's performance in neighboring Indiana which is demographically was absolutely insane.
My thought is that back in the early 2000s, where you invested in campaigning mattered a lot more in swaying the final results. In both 2004 and 2008, both sides invested heavily in Ohio, so the results were less prone to wild swings and less reactive than the nation at large. In the case of Indiana, Obama invested in 2008 whereas McCain did not hence the wild swing left. If one looks at a 2004-2008 County swing map, a very clear divide can be seen along the Indiana-Ohio border despite the counties being demographically similar.
Because today media is so widespread and we have much more polarization, the value of investing in a specific state has gone down, and investing in specific demographics that could swing elections in key states has become more important. In 2020, nearly every swing can just be explained by a combination of increasing educational divide, increasing religius divide, increasing urban-rural split, demographic changes, re-alignment lag, and a decrease in racial polarization, most notably with Hispanics swinging rightwards. There are almost no parts of the Country in 2020 where you had swings that really bucked the demographics of nationwide swings.
