The Dow drops 800 points as trade fears ratchet back up

Stocks plummeted Tuesday after optimism for a US-China trade deal faded and as Treasury yields fell.
Global markets had rallied a day earlier. 
Watch the major US indexes trade in real time here.Stocks fell sharply Tuesday after optimism for easing trade tensions between Washington and Beijing waned and as Treasury yields turned lower, stirring worries about the prospect of slowing economic growth around the world.
The Dow Jones Industrial Average dropped 3%, or nearly 800 points. The Nasda