From a European perspective, I think that the establishment found it easier to implement the UN Agenda 21 under the banner of Social Democracy + alliances with Green parties.

As a result there is a general overlap between social democrat parties and the establishment, vs populist parties and anti-establishment movements.

This makes sense when we consider taxes, schooling, environmental policies, property rights, media control, moneyprinting in exchange for votes et cetera. These are all easier to achieve from a social democrat platform, even if there are authoritarian overlaps with the more extreme religious conservatives. 

 Fascinating chart. 

Suggests mainstream media is just as much an echo chamber as social media. 

 Pluralism vs universalism. 

 The numbers check out. I suspect Republicans are susceptible to trusting mass media when it aligns with their views which is practically never. 

 The R breakdown in early 00s seems odd. What happened there? WMDs? MSM was still strong then, but maybe they started seeing through it anyway with the rise of the internet.