A Salon article says that Trump's
trade war of choice against China has turned a steadily rising Dow Jones average, through 2017, into an unstable sawtooth pattern with massive single-day declines that are now tempting a full-on 2008-style collapse.
Leaving aside the prediction-like final part, is there some quantitative way to assess if there has been more US stock market instability after 2017 than in the period before? (Obviously starting sometime after the Great Recession.)