I personally think they went through a meaningful shift from being evil but effective in their own way (in advancing their own agenda not in solving actual problems) to transparently stupid, and - genuinely unhinged Jewish space lasers, nuking tornadoes, drinking bleach, buying Greenland, and staring directly into the sun.

They've gone from cynically exploiting culture war nonsense to advance class war to believing their propaganda and losing the plot - I think the rise of the tea party was the inflection point.