US exports make up 11% of GDP. Of that 11%, some fraction is facing retaliatory tariffs.
Considering the DJIA went up 4,000 points from Dec then crashed 4,000 points in Jan, one should be careful assigning cause when it did it again from Jan to Mar.
A lot more than 11% of GDP relies on various imports randomly being subject to tariffs (on everything from steel and lumber to electronics). This is effecting everything from manufacturing and construction to retail.
This is a problem, but it's not the current problem. The pain isn't coming from defaults [1]. It's coming from our export industries.
[1] https://fred.stlouisfed.org/series/DRALACBN