I think economic stress is more an underlying foundation than a trigger for strife. Certainly, a sudden crash could exacerbate things, but the perception of great inequality (Tax The Billionaires!) lays a groundwork for other dissatisfactions. The Left always presents this as class warfare but, in reality, unfettered immigration is a huge driver. The pressure on housing has led to sky high rents and great difficulty in youth access to home purchasing. The downward pressure on wages from illegals working for significantly under market and under the table, makes job seeking particularly difficult for our entry level citizens.
The Trump recovery, job on-shoring, and US energy production may put this in the background, so long as the benefits make their way down to the lowest levels.
KatNap Fever! 