Trump has been threatening and posturing for 10 years. The second he was elected the economy started to react to everything he has said and done up to that point.
He's been indirectly impacting the economy for years, and directly impacting it since November.
He was allowed to run because McConnell stonewalled Obama and let Trump select a bunch of Supreme Court appointees, which then decided that trump can't be held accountable for anything.
Then everyone decided the rule of law was important, except trump, which means he's steamrolling every safeguard we had.