You find lots of defectors in homogenous states. Texas is flush with libertarian conservatives who believe they aren’t served by the GOP. California has it’s fill of socialists disgusted with corporate shills in the “liberal” party.

Swing states have to play friendlier with these types of voters, producing lots of oddball candidates like Dennis Kucinich and Ilhan Omar. One reason Dem Senators are running so far ahead of Biden is due to their moderate appeal in their states relative to his extremist views.