I'm shocked its even that many
Fewer counties = fewer chances to deviate from the previous year's trend. This explains WY, NV, MA, and AZ. WV and OK were literally maxed out for Republicans and don't have a suburban constituency large enough to flip D - MO, OK and ID are pretty much the same considering urban centers weren't going to flip R.
The most notable example here (hardest to explain) is Louisiana.
Precisely. Western states, such as those in the map, don't have many counties and even fewer are even close to competitive.
Honestly, the only real surprise on this list was Louisiana. OK, WV, MA and HI had (at least in 2016 in the case of Oklahoma County) all their counties go one way in both 2012 and 2016, so they make sense. AZ only has 15 counties so no flips makes enough sense. In WY, NV and ID there are a few counties that are safely Democratic or at least Democratic-leaning that supported Obama and Clinton, while the residue are heavily Republican. In Missouri, similarly, there are a few heavily blue counties in blue areas (college-oriented Boone County, St. Louis and St. Louis County and Jackson County (Kansas City)) while the rest are all quite red - the closest Trump county, Clay (suburbs of Kansas City), went red by around 11 points. KS has some blue counties and in 2016 some were trending leftward (see Riley County, which voted blue in 2020 for the firs time in literally forever), but counties such as Riley and Johnson, both of which made the transition in 2020, weren't quite there yet. The few blue counties, such as Douglas and Wyandotte, were all blue enough that they give Clinton over 60%. Louisiana is the only big surprise, though technically no counties there went for Clinton or Trump (they have 'parishes'). It has a huge number of parishes. Even LA makes some sense though. Trump's core voters generally constitued majorities in the rural counties that were already very red. The blue counties were urban and/or majority African-American. The only close counties in 2012 were Caddo (an urban county in the northwest home to Shreveport) and some rural counties (Bienville, St. Landry, Red River and Morehouse). It would make sense for Clinton to not underperform Obama by 4 points (his 2012 margin) in an urban county, and similarly there was no way the close rural counties that backed Romney were going to suddenly flip for Clinton (and they didn't - all trended rightward).
