Obama came very close in '08, which was obviously a Dem high-water mark. He narrowly won Indiana the same year.Dancing around the 270 to win EC map and some polls....
What the hell happened to MO? Wasn't that a "purplish" state within the past 20 years? That thing is redder than an Irishman on the equator at noon.
I think the Midwest overall has shifted. The purplish states like MO and OH have become red. The blue states, infamously, have become purple. Iowa had something like a 19-point swing from 2008 to 2016.
This is just a guess on my part, but I suspect that the Rust Belt areas have become more amenable to a populist message, while the southern-ish parts of states like MO and IN have just become more straight-up conservative.