The cause is Trump et al's rhetoric of lies to rally his base, along with the problem with the political system and mainstream media - more specifically, the duopoly and how mainstream media conglomerates that perpetuate whatever industrial complex fed narratives for "their side" want, leading to only two core mainstream narratives for either the Democrats of Republicans.
Andrew Yang's main policy proposals would break apart the duopoly - expanding the narratives - and take power away from the current mainstream media companies:
- Freedom Dividend/UBI so people can think clearly with less stress,
- Ranked Choice Voting so people aren't wasting their vote and don't feel obligated to vote one of two incumbents,
- Democracy Dollars to wash out lobbyist money from industrial complexes/bad actors by a factor of 8:1 (via $100/year to every eligible voter to contribute to politician of choice),
- Journalism Dollars - same idea, each citizen can "vote" with money allocated to them for journalism - local or national to cover what they have interests in knowing about.
I think I'm forgetting another core policy - but also he wants to implement a government option for healthcare similar to "Medicare For All" - but not killing off private insurance due to the consequences of disrupting that industry immediately - will all strengthen Democracy because it's strengthening, taking care of, people.